Oh yeah, I agree as just a general social standard, men are expected to initiate the conversation, show that they're interesting, ask the woman out on a date, etc. It's not black and white like you said as not everyone works within these confines exactly but in general that's how things go. That said, I would say that both men and women stress over and worry about initiating messages on dating apps. It's just that with the general standards of dating we operate in, if you're a guy, if you don't get over that you're not going to get many dates while if you're a woman, there's really no need to do that since guys will come to you.
So I think what ends up happening is as a guy you get Bumble thinking "oh women initiate messages here, that takes some of the pressure off" but then you realize that fundamentally, there's not really much of a difference from Tinder and other apps like it from the guy's perspective because the expectation is still the same. It's a little disappointing and I can see why some would complain about it and not feel like putting effort in if the other person is giving you a generic, boring message. Especially when you sense that there's an expectation for you to entertain them essentially. Just that sense that the person wants you to be super interesting but have little to offer of their own. I mean, why should anyone find them worth a conversation?
Personally, I just found Bumble to be a similar experience to what I got on apps like Tinder except there were more barriers. I used Tinder, OkCupid and Bumble at the same time and Bumble was definitely the most lackluster experience out of the 3. For women I can totally see the benefits. As a guy though, I think it's fundamentally worse than the other apps.