If you want to confront someone on an issue, your own self-control is paramount. It isn't just their potential defensiveness you need to think about. First and foremost, your self-control. Shoot for these goals:

Specific, Actionable, Sensible, Accurate.

SASA.

You also need to give them Space to agree or disagree. If you go in with the attitude that you'll bully them into submission, that may not go very well.

SASAS.

Maybe a better way to present the last one would be Willing to listen and give them the space to agree, disagree, clarify, take some time, etc.

SASAW.

Specific, Actionable, Sensible, Accurate, Willing.

Specific: They need to know what you're saying. Vague claims like "You don't care" are difficult to assess. Better: "You don't care about celebrating my birthday."

Actionable: A person not only must be able to do something about your complaint, they must also come to that realization. A person able to do something they don't know they can do probably won't do it. "I'd like to go to a nice restaurant on my birthday" is actionable in a way that "You don't care about celebrating my birthday" may not be.

Sensible: Not only should it be generally regarded as sensible, but it's important for your listener to see how it's sensible. Getting this across is part of confronting them. People won't respond well if you confront them with demands they don't find sensible (even if they are Specific, Actionable, etc - even if the demands ARE sensible, the person has to realize that, or it probably won't work). "I celebrate your birthdays the way you want. Why are mine always secondary? A nice meal seems like a nice, normal thing to do in general."

Accurate: You may feel that if you phrase things strongly, people will hear you better if they weren't hearing you before. Sometimes this is true. But it's a double-edged sword. You can just as easily shut people off by exaggerating or throwing in dubious or incorrect extras. "You've never, ever cared about me, even to show up at a nice restaurant to celebrate my birthday with people who are your friends" could be off-putting and unpersuasive to someone who does care and/or has celebrated your birthday at times. Often understatement works better than overstatement. Go for what no one in their right mind can deny. Don't go for the big emotional wow-factor. "You've celebrated my birthday before, but not in the past 3 years." Or, to bring back the example used under Sensible: "You don't seem to care about celebrating my birthday" is even more specific and accurate than "You don't care about celebrating my birthday." Someone might feel they care - or there might be other factors getting in the way - and that might not be getting communicated. But if it seems that way to you, that is an accurate, specific statement that it seems that way to you. It allows people to see your point even if they believe they do care very much, for example. Otherwise, they might be forced to simply disagree: "But I do care!" which will possibly lead to you feeling invalidated, brushed aside, gaslit, etc. "You don't seem to care about celebrating my birthday" is pretty easy for anyone to agree with, even if they kind of don't agree with the premise that they don't care, as long as they recognize you have feelings on the matter, and they care about how you feel. Make it easier, not harder. This example is easier because it's actually truer. You know how it seems. You don't actually know how the other person feels. Stick with what you know for sure.

Willing: I'll leave this mostly to you, as it means many things. It's a bit of a wildcard, as it's about openness and adaptability. But one tip is: Don't tell people what they mean. If someone says a thing and you don't like it, and you push back, allow them to adjust. Don't try to pin them to your interpretation. Don't make it a cross-examination. Let people tell you what they mean, and what they meant, even if that sometimes involves allowing them to change the story a little bit. You will thank me. Trust me on this. It allows people to make the little changes their own. Also, be willing to see people as real, whole people. Don't try to reduce them to categories because you happen to be upset with them. Allow them to be real and multifaceted. Be willing to let them be them. They can tell the difference.

Often people will not agree with you at first, but if you observe these principles well, you'll find that they drift toward agreeing with and accepting and respecting you, more often than not.

Alternative: Non-Confrontational Storytelling

A great technique is to tell a short, personal story about something you experienced and learned. Present it as your own unique experience, not as theirs, not as some eternal truth. Allow yourself to be fallible in that story, but open to learning. Then just move on to some other topic, or some other activity you have lined up. This gives just about the optimal chance that someone will actually change their mind about something you bring up. Rarely will a person change their mind on the spot when confronted (especially if confronted angrily). But quite regularly people change their minds over time because they know people who see them as real people and recount some of their experiences, and listen to experiences in turn. It's a lot less confrontational up-front, but it gets a lot more work done over time.

You can be frank about what you believe, but own it as your belief, and don't beat someone over the head with it, or act like they must accept your belief. Saying "I think Coldplay is a great band" is very, very different from an extended argument in which you try to prove Coldplay is a great brand in such a way that the other person feels you are giving them no option but to agree, whether they actually agree or not. People will almost always accept personal sharing along the lines of "I think Coldplay is a great band" as long as you allow them their own opinion just as freely as you share yours. This kind of simple, personal statement exposes people to other views without threatening, guilt-tripping, or otherwise trying to control the situation. It's much more effective.

Still, sometimes we all do need to confront people. You might want to use SASAW, then, or just keep it in mind as a reference point.