This is one of those double standards we all accidentally buy into. It’s disgusting, really - a girl’s unreciprocated feelings for a guy are considered desperate, clingy, something you need to shake off your leg. A guy, on the other hand, is seen as determined, confident, passionate, someone who deserves a chance.
I’ve never seen this in my experience. He is seen “as desperate, clingy, something you need to shake off your leg.” I’ve never regretted and neither have any of my friends regretted loosing an acquaintance of the clingy guy from school or wherever. It’s not unfair to feel uncomfortable, but it needs to be dealt with quickly and carefully and hopefully not lead to anything terrible.