It’s important to remember, though, that people are allowed to vent when they feel frustrated. There’s nothing wrong with ranting from time to time. I can sympathize a lot with the OP because I have met my fair share of bad/lazy players—and I’m not talking about newbies, but veterans/mentors in endgame content that cannot fulfill the very basics of their roles (e.g., a tank using mitigation for tankbusters in Rabanastre when it’s very obvious they aren’t new to tanking or the instance).
Also, there is absolutely nothing more frustrating than carrying a player, and them walking away with all the loot, be it primal mounts, weapons, or Savage gear that you needed. Better to let off some steam—and for some, that is best done with a healthy little rant; I am a frequently poster in the Tales of the Duty Finder thread—than to just bottle it up if you’re the type who cannot just shrug it off/just not care (and there are a lot of people like that).