It came across to me as "keep your batteries always under 0 C", which obviously almost nobody can do, and it leads to a sense of "eh, I won't go to these lengths, might as well do nothing", which is counterproductive.

I see the same reaction with healthy eating, where people are so put off by extremely militant advice that they think "I can't eat only vegetables all day, fuck it, I'll eat these three cheeseburgers".

I agree with your second comment, the first one just could be misconstrued as very hard-to-follow advice.