I disagree completely. If you post something racist on LinkedIn you're probably going to lose your job. Try it, if you don't believe me. If you post something racist here you're going to get downvoted.
This can be read as why to avoid LinkedIn. Job searching is already hard, if you manage to land an interview you still have to spend time, as an old dude, studying Leetcode like you're a kid with five years experience instead of twenty. Then it's competitive. Etc.
So to this you wish to add the increased risk of negative exposure by saying a bad thing? Or that someone, someones, or people five years from today consider a bad thing?
I love writing and posting and engaging (you can tell from my history here alone), but I'm not crazy enough to risk spilling my feelings on a site full of people in suits and ties, with Leader next to their names.