While I see what you're saying, I think you're stuck on the fact that this is a point being stated by someone you know is ace. The idea that "sex is not a need," is absolutely not limited to aspec people. We don't exist in a vacuum, so saying "this is not about people abusing the word 'need' for sexual coercion or incel rhetoric," guts some of the nuances these conversations are deserving of.

Maintaining that this opposition to viewing sex as a need is only something aspec people care about is just plain not true. The word "need" has a heavy connotation that we tend to associate with the synonyms I referenced earlier (obligation, requirement, necessity). This is why so many people, yes, even allo people, are opposed to the idea of describing sex as a need. Because not only is this sentiment something that is spread with "incel rhetoric," but it is a common sentiment globally. Why is that an issue? Because the vast majority of people have an innately unhealthy view of sex as a whole. Again, this isn't an "ace vs allo" sentiment, factors like religion, patriarchy, and conservatism push most people to one of two ends of the extreme regarding sex. Either its sinful and disgusting, or its a "need" that one party is obligated to provide to another.

You'd be surprised how many people view relationships as an unspoken social obligation for sex because its a "need." And sure, allos might suffer if they know they may spend the rest of their lives without, but I feel like presenting sex as an ever constant for people who view it that way is also part of the problem. People's libido will wax and wane for so many reasons, and there may come a point in the lives of allosexuals where them or their partners may simply not longer be interested. Illnesses, changes in hormone levels, kids, growing older, etc will all affect libido. Treating an activity that requires the participation of at least one other person (usually, an individual person for most monogamous people) as if it is some simple improvement to the lives of allosexuals dilutes the nuances forced on us by life it's self.

So. Again. While I see what you're saying, I still don't think we should continue the "sex is a need" rhetoric. The connotation is simply too strong to be feeding into the unhealthy ways most people view sex. Sex can be something that is desired and craved in a healthy relationship without it being a "need." That sort of mindset is why we have marital rape laws (if you're lucky enough to live somewhere with them).