I can't speak for other men, but for me personally it's a mix of things.
Us men are expected to take initiative and approach women as women have the upper hand in terms of being approached (ad absurdum, a trip to the grocery store and back results in 50 compliments, 45 approaches, and 37 date offers). Us men are supposed to know exactly what kinds of "signs" are indicators that women may or may not be interested in us, all the while those signs are completely arbitrary and for many we more often end up with false positives than actual positives on detecting the signs - let alone act on it.
All the while, plenty of women complain about being approached by men when they don't want it or apparently weren't giving "signs", complain about why some men don't pick up the signs and why they won't just talk to said women as they "should", etc.
Silly as I am, I'd rather not take the high risk of inconveniencing others by approaching them when they don't want to. I wouldn't halt other random men walking down the street clearly in a hurry just to start a lengthy conversation just because I feel like doing so, either.
I don't even care about the rejection itself on my end, that's part of life.
If a woman is clear enough about her hypothetical interest in me, I don't mind doing the approaching/asking her out or something. But, in my experience even continuous physical contact on her end is far from a guaranteed interest. Hell, I ended up making out with some women at parties and they weren't interested in dating. If all that is no good indication, how can I consider a smile or looking more than a second in my direction as "clear" signs? I just don't know what kind of "signs" are close enough to a guaranteed interest for me to act upon anymore.
Which brings us back to about the one most guaranteed thing: them approaching me and asking me out.
I'm clear with my interest, even have had several times I straight-out told a woman I like her. False positives with me would be rare.
By no means am I obsessed though, nor meaning to whine about it. But, I simply no longer feel like being the one putting in 99% of the actual effort as I'd rather have it be 50/50; much like I'd want a relationship to be like, equal effort and investment and all that.
Instead, I focus on myself, do things I enjoy doing and have the whole dating on the back burner for now. No risk of causing discomfort to others, no wasted energy nor time (or money), almost guaranteed enjoyment, etc.