There must be some magic to being 155lbs. While I can't vouch for the truth of some posters here, I can vouch for my own (which, as always, is then on the populace of this board to believe). I weigh 155lbs. I often run without a shirt.
I have received many hateful comments, [most] likely pejorative laughs (both of these largely stemming from male insecurity with sexuality, physical appearance, and confidence), been physically threatened, but also been greeted with all kinds of love.
It's true, the catcall moments are rare in comparison, but sadly it is nice to be call sexy (mockery or not), be high-fived from cars, see someone take a photo of you from their car while saying "ow ow," and even perhaps my personal favorite: I was stopped at an intersection and a female driver ran a light because she was distracted. The cyclist next to me said, "pretty sure she almost got in an accident because she was staring at you." Was it true? Who knows, but the cyclist's comment alone made my day.
As a fairly skinny white guy, I have found the most consistent vocal fan base is black women, many of whom are older and a little less than trim. I actually might say that their enthusiasm and forthrightness is the most satisfying. It's just showing appreciation in a playful way.
Not every comment about appearance needs to be linked to a sexual encounter. It should be okay to comment on someone's appearance positively and not seem like a creep.