That's what I would expect. A typical male YouTuber voice is still going to be quite loud from 100-300hz or so, probably. Here's a quick REW peaks(you will clip at peaks) RTA of the first 45ish seconds of HDTVTest's newest video on my system:
He's definitely not a super bassy YouTuber either, but you still see high levels at 100 and 200hz, and since Genelec's capability is maybe 6-8dB lower below 250hz(assuming some boundary reinforcement), that's where the clipping's most likely to happen.
You will see the same on music, even with female lead singers and perceptually little bass. Keep in mind that below 200hz we don't hear bass nearly as loudly as the midrange, so if it sounds like there's little bass, there is probably still quite a bit, and if it sounds like there IS bass, there is probably a *LOT* more than any other frequency range.
I didn't realize that GLM didn't allow bass managed sub configurations with the W371A, but it's not surprising, as bass management in general isn't very popular in studios compared to home setups They don't need it as much since the rooms are usually designed from the ground up to resolve any bass issues. In a multi-channel system you can(and studios do) use sub(s) for the LFE even with the W371A of course.
Also I think a lot of people don't realize just how powerful the W371A is. It has both a 14" and a 12" driver with 400W/ea of amplification for a total of 800W. That is significantly more driver area than even a high-end 4x8" floorstander.