@mommunism
"Beta cucks" in this context refers to indicisive protagonists who're interested in girls, and the girls show interest in them, yet nothing happens for dozens, sometimes even hundreds, of chapters despite the story having a romance tag, and the biggest culprits these days are isekai stories. It's gotten to the point where a sudden sex scene is considered a refreshing change of pace.
The only story I can think of at the top of my head where the MC has a legit reason for not going after the girls is Exterminator. There the MC clearly says he's not doing it with someone he has no interest in. If more stories were like that, the beta cuck label wouldn't exist but alas we're stuck with indicisve protagonists for the most part.