If I have made an accidental kimchi bomb then I will want to defuse it safely before I dispose of it. If I put it in the trash and leave it for the refuse collector there is risk that it blows up in their face without any warning. That's a much worse outcome. The root issue here is that this thermos design doesnt have a way to safely defuse it.
(That hamster-microwave thing is a disinfo campaign from manufacuturers to limit liability of corporations, BTW, see also https://en.wikipedia.org/wiki/Liebeck_v._McDonald%27s_Restau...)
Seems to be like they sold a bottle designed for a pressure relief cap with the wrong model cap, turning food storage containers into launchers.
I said "given it should be there" because Thermos have just issued a recall notice where they openly admit liability and they openly state it should be there (see side by side photos in the recall).
I was never seeking to pass judgement on the factual element of whether "it should be there" in the pure definition of the term.
I was just saying "it should be there on THAT product because Thermos says so".