I work in a male dominated environment. Always have and I can tell you that sexual harassment is commonplace. It's not as bad now but it's still there. Flirting hasn't changed- that still happens, it's healthy and very different from sexual harassment.
It's interesting how it's changed for me as I have aged, as I have progressed and as times have changed.
I went from being the target as I was new, young and inexperienced in both the workplace and life, to being "one of the lads". Or, as I now see an enabler, co-conspirator. I felt lucky to have been accepted as competent, part of the team. This should have been my right. I was competent. I was part of the team. I dismissed it as banter, letting off steam, a laugh. The women involved knew what they were getting in to. They had a choice 
My DD entered the workplace as the whole #metoo movement blew up and it caused me to take a long hard look at myself. I now call it every time I see it- from the "jugs" comments every time an attractive woman walks in to the room, to the often married men who flirt with/harass the assistants, the juniors. They don't target their attractive colleagues who are the same age as their wives. They wield their power over those that have less, thus compromising their ability to say "no". They moan in the same way the OP has about how they don't know where the line is anymore- I tell them every time where it is because it's really clear! They've stopped moaning to me. Don't share the misogynistic crap they once did with me and guess what? Treat me like an equal, for the first time ever.
Whilst we make excuses for them, laugh along and sympathise with their bull shit, we are complicit. I was complicit, despite being targeted, despite being raped. I am thoroughly ashamed of myself for that. As a result I will do everything in my power to protect others not in my position of power. To protect my DD