Thank you for understanding what I was trying to say!
I was starting to feel like I wasn't wording it right at all.

I agree with you - the bolded does seem to be a big part of the difference between many posters on this thread. I posted earlier that I don't think either approach to dating is better than the other. They are just different. The people who are more casual about it are not at all likely to consider whether they'd be happy spending the rest of their life with the person they are considering going out with. They are more concerned with whether they are going to enjoy that specific date with the person. And there is absolutely nothing wrong with that at all!
The people who view dating as more of a process - you go on a date, if it goes well maybe it develops into a more serious relationship, eventually maybe you fall in love, etc - are probably less likely to go on that first date with someone they have a major difference with, just because they don't want to deal with the complication of that difference if they become more attached to the person. If you are that type of person, why progress beyond friendship with someone you already know you aren't going to be happy with longterm, if you can just stay friends with them and date someone more compatible instead? And there is nothing wrong with that approach, either. I was just trying to explain the school of thought that would lead to someone not dating a person that lacks a particular quality that is important to them, and how that choice doesn't mean you think they aren't "worth your time or love". I'm starting to feel like this is one of those issues that some people either get or they don't, which is weird because it seems totally logical to me. (Not that you have to agree with it to understand it, obviously.)