There aren’t any lesbian bars, sadly, but I would expect bachelorettes to hit them if they existed. The point seems to be “act slutty and let their guard down without risk”. (Though as a gay woman I have a whole separate rant about straight women in gay bars.)
I have some sympathy for them. The whole point of gay bars is having fun and expressing one’s sexuality without risk. But each party is having a “once in a lifetime” drunken blowout, while for the rest of the bar it’s just a Friday. Also they bring extreme straight energy.
It used to be less common, but then their behaviour was worse when gay culture was less mainstream and they treated it like going on safari. It was also galling when they invaded our space to celebrate marriage when we couldn’t marry, then turned around and voted Republican.