Let me first say this.
Being a nice guy and expecting some sort of romantic interest from the other person and being mad when they don’t have it is childish and inexcusable. Be a nice guy and flirt, and if you get rejected, either keep being a good friend or move on and don’t be a whiney bitch about it (sure, be sad, being rejected is sad, but you can’t blame the person for rejecting you and you need to suck it up eventually).
There are times when the mythical friendzone exists, and it’s not an okay thing to do to someone.
The problem is the word “friendzone” is misused, and anytime we hear it now, we think of the first context. In that context, you’re being a misogynistic whiney little fedora wearing ass-clown, and you need to get the sand out of your ass and dick-hole and move on.
But here’s the other context:
Sometimes people (women and men both) make a point to use other people. When a person finds out someone else is interested in them and deliberately strings them along by letting them flirt and never saying they’re interested and never saying they’re not interested, simply because they enjoy the power that comes from having someone follow you around like an eager-to-please puppy dog isn’t okay. Especially when the person is forward about having a romantic interest.
It’s manipulative and kind of gross. If the other person is clearly interested and you’re not, tell them you’re not interested.
If they keep wanting to be your friend, Great! (And in that case it can get a little weird then in terms of whether you’re maintaining a healthy platonic relationship or if you’re still sort of manipulating their interest in you.)
I’ve seen it done by both men and women, and it’s really kind of cold and sick to deliberately use someone that way.
Rephrasing again for clarity so people don’t misread and get angry: Yes, complaining about someone not developing interest in you/rejecting you when you’ve been friendly to them is bullshit. They’re completely within their right to be attracted to and not attracted to whomever they please. Get yo sexist shit outta here.
But there is a difference between turning down advances and leading someone along by the nose becuase it’s empowering to have someone who finds you attractive kiss your feet.