I don't actually know why people even care about cheaters (and this is not in anyway related to mods, even though some argue it is) getting achievements anyway. Personally I don't feel insecure if someone else gets a hard achievement with no effort, if anything they're the ones missing out on the fun of getting it.
I agree, I don't understand it either, but some people do get terribly uptight about how others enjoy their solo experiences and it is an ongoing thing.
It's a problem I've seen with other games too which in spite of its inconsistency suggests that Steam may well be the common factor, though I admit that if there's a problem and Steam is involved, they're automatically top of my list of likely suspects. Other games where achievements are disabled if mods happen end up with mods to re-enable the achievements anyway so it all seems a bit of a pointless faff.
