There's a difference between showing off a technological marvel like a nuclear submarine and not really focusing on its applications as a weapon, versus showing off a weapon and being like "it's so cool to kill 'bad guys' with this stuff"
And yeah he probably hasn't been shy about it, I don't watch his videos religiously. I found out during his excellent talk on the Artemis program. IIRC, he mentioned he helped design missile countermeasures, which is pretty tame as military industrial complex goes, but it's still participating in the amelioration of killing machines, which doesn't sit right with me. And he talked about it so nonchalantly, like he hadn't considered that the people at the end of the barrel of the weapons he was helping design obviously were the "bad guys"
I still have a ton of respect for the guy and his educational outreach work, and I don't hold it against him, I just don't get how someone could sleep at night knowing that they helped make weapons more efficient at killing people.