The term used to be called "unrequited love", and it goes back much further than the internet. It has existed for all of human history. It is where a person experiences non-openly reciprocated love of a another. Typically between a young man and a young woman where the man experiences it, but it can go the other way too and it does. It used to be considered a sweet innocent occurrence between a young people because they are new to relationships. Even in the media, it was the driver of a lot of Rom-Coms, teen TV shows, coming of age shows/movies. It was never seen as a problem IRL or in media, but something that just happens with inexperienced and/or young people figuring out life.

But for whatever reason, thanks to feminism and virality of the internet it is now seen as a problem. I think a media amplified problem that isnt as severe or a problem at all, but the internet and media never lies right?

Remember Ellen Pao, the interim Reddit CEO tweeted that "incels are a problem" and asked the government "what are you going to do about it?" Probably after Elliot Rodger did his thing.