By definition a generalization is an average of.. everyone. On average, Tinder is used for hooking up way way more than it's used for serious relationships.
The people I was responding to were saying "Women use Tinder for sex" (implying everyone), and "Everyone knows what Tinder is. It's a hookup app." (implying everyone)
My comment was to point out that you can't say things like this without implying that 100% of people feel this way, which is not the case.