I would like to extend this point: "I'd rather have Linus Torvalds telling me I'm an idiot and my code is shit, than ... releasing kernel with my shitty code and EVERYONE thinking that I'm an idiot".
Of course there exist examples of Linus calling or even implying that individual people / organisations are "idiots" and they are wrong (and he has acknowledged this). But in the vast majority of cases the criticism is aimed at the code itself and I genuinely don't see the issue with this.
They could just refuse your code without calling you an idiot.