Another way to look at this is: how often are we hitting the flop and getting paid of on our bad hands and how many bbs are we giving up in the long run.
The former is a bit hard to say as it's it's hand dependent but, in general, weaker/mediocre hands aren't hitting and getting paid often enough to warrant a profitable call.
If you're constantly calling off in the small blind, that's 10 bbs in 20 rotations. That might not be a lot in early stages with deep stacks, but if you get deeper and your stack is smaller, giving up 5-10+ bbs is a lot in comparison. You'd rather have those extra 5-10+ bbs for spots you want to play to maximize your value than spew them off in spots where you're going to giving them majority of the time.
In this situation, and this might just be personal opinion, chip preservation is a lot important than playing a spot where you're getting good odds preflop to play a mediocre hand that might hit sometimes and you may/maynot get paid paid off on. I don't think that happens often enough and I'd rather just fold and play a guaranteed +ev spot with more chips in my stack.