I agree to a point - but to play devil's advocate:
We veteran players need to be aware of how we come across when we give advice. What we perceive as helpful can come across snippy. I am currently levelling my PLD. I have levelled all DPS and healing classes and know a lot about the game, but I always warn my party the first time I am tanking a dungeon, especially if I haven't run it in awhile. I had one dungeon left earlier today to get the challenge log bonus after completing my roulettes so I changed to my PLD and queued for low roulette again since Tank was class in need. I got Stone Vigil, which I haven't even ran in quite awhile. So at the start of the dungeon, I said "Hey - been awhile since I ran this and first time tanking it, so apologies in advance if I forget a mechanic or something."
Two seconds after I posted that in chat, the healer replies with "SHIELD OATH" and then "You better mark targets and rotate properly if you want us to stay alive or the dps will take all the hate off you." From their perspective, those are two very useful pieces of advice - and as someone who's run this on DPS and healing classes, I agree with their points. However, at first, it came across to me as bossy and a little rude. Granted, I just put on Shield Oath and started to pull, but someone who takes that stuff seriously would have turned that into a drama fest. Advice isn't always wanted or needed. I usually wait until after a wipe or until someone asks a question to throw something out there. Or if I see something someone can do that they aren't, I ask if they would like a helpful tip. In this run, I knew how to tank the mobs. If I wasn't sure where to tank a boss, I asked.