So, rookie mum and former lurker here. Couple of reasons I can think of.
First reason I do not mention it to my gym parent friends is that I don't talk to any of the other parents. We all used to sit/chat/pretend-to-work in the lobby while waiting for our little pride and joys to finish their sessions and talking definitely happened (I may have even mentioned ChalkBucket), but sadly Covid has put a stop to that. We now drop them off and sit in the car, do the grocery shopping, go home or do whatever else we do to pass the time. My little one hasn't had any competitions yet either, so again no parents to talk to during the waiting there. I am assuming this will come back in the future, but we're not quite there yet.
Second reason is probably that we live in a small country with not that many clubs and sometimes that makes it difficult to talk about things that are very specific to this country or our club without outing ourselves. A lot of the things that are talked about are also very specific to the USA, so need to comment if you are not in the USA
Third reason there is already a lot of information out there. A lot of the questions that I had as a newbie gym mum have already been answered many, many times: is X hours too much (depends), is my gymmie going to the Olympics (highly unlikely), should I buy her a beam/mats/bars/grips/etc (nope/guilty/nope/nope), do I mention Y to the coach (yes, probably). I didn't feel the need to rehash all of that, so kept lurking.
Fourth reason, learning what DD, JO, FX , WAG, etc. stand for takes time and a little lurking is great to just learn the terminology (although a glossary with commonly used abbreviations would be so helpful!).
Final reason, you are all wonderful people, I am sure, but all you veterans with six kids doing lvl 10/hopes/elite/whatsnot, you can be a little intimidating. Your children are doing some serious time in the gym, have been there, done that, are wondering which college would be best and then there is my little one who could barely do a rolypoly. Now I know, everyone is super helpful, but some of us probably feel a little bit like an 8-year old talking to the coach.... it is a bit scary
Anyway, just my thoughts