@Nestrior:
Only the "yaoi" tag in particular has this weird hard-line convention around it like that, it's understandable not to know.
Honestly the term has some weird history; legend has it that in japan it's an acronym standing for "no climax, no conclusion, no meaning," or, basically, "plotless gay porno". Obviously that's not how the western fanbase is using it; as you've discovered a non-trivial portion of this stuff is actually quite well written (though of course there's also a lot of utter garbage), and can be quite powerful or endearing.
Though it definitely also has as a genre a general trend towards certain key flaws—one will run into a lot of suddenly-casual-sex (at seriously WTF levels, like if two polite people just met and were having a nice chat and then suddenly the pants are off and it's go time), a really uncomfortable relationship with the idea of consent or with sexual-abuse-portrayed-as-love, and a tendency towards really narrow views of homosexuality (there is a fixed 'pants' and a 'skirt' in most yaoi relationships to a greater or lesser degree).