This really annoyed me towards the end. The Watchtower doesn't do its members any favors by frequently warning about stumbling and offending each other. It's no surprise that this becomes a cult control tactic where you can't even groom yourself the way you want because it might be "cause for stumbling".
With so much emphasis, it became wussification and contributed to the toxic environment of Jehovah's witnesses. Typically, they don't seem to take criticism very well, because criticism is also "stumbling". This is well demonstrated in the school when someone gives a talk.
If someone is so bothered by another person, they can take it up with them, but in too many cases, out of political correctness, they just don't. To be fair, that has been recommended, and the Watchtower has stated that being overly offended shows a kind of selfishness.
But they're the ones repeating the message all the time and translating "grace" as "undeserved kindness". They're the ones using this same idea of stumbling as a behavioral control tactic. They're the ones that tell bodies of elders to give "warning talks" (marking talks) about a sin supposedly committed.
As @debihope said on Twitter (and William Gibson retweeted): "Before you diagnose yourself with depression or low self esteem, first make sure you are not, in fact, just surrounded by assholes."
Don't be an asshole, and don't surround yourself with assholes either.