Not necessarily. The way you sit at a drum kit, angle your arms and even hold the drumsticks differ on real kits than they do on the Guitar Hero kit. The technique matters a lot because you use the flex in the drum skins to help with your movements and thus allow for tighter patterns and reduce the risk of RSI. This same technique isn't transferable to Guitar Hero and nor would playing Guitar Hero make you a competent drummer (due to teaching the wrong technique).

I agree it's not 100% the same thing but it's much closer than playing a plastic guitar.

Being an excellent GH drummer might make you (a mediocre) drummer IRL. Being an excellent GH guitar player won't make you even a beginner guitar player IRL. It's not "an entirely different skillset", it's a relevantly close skillset as long as drums are affected.

My point is that being a drummer, even a mediocre one, is all about technique and that technique differs on a real drum kit vs Guitar Hero drums.

While superficially it might look the same, drumming isn’t just about hitting objects in time. How you hit those objects is what really matters but GH doesn’t train that skill.