That's true... but a normal server has no way of connecting your IP to your Bitcointalk username... unless it is is the Bitcointalk server (or they somehow hack the Bitcointalk logs) 
But OP could still create a link between the username and the IP, even without explicitly asking for it.
At least if not hundreds or thousands of user will ask him for the server details in a short amount of time.
But even if a connection can be established, i don't see the problem with it. It's not like your account or anything is at risk if such a link exists (especially since most people have dynamic IP's which regularly change or beacuse they are sitting behind a NAT of their ISP).
Don't they get your ip and xpub keys?
So it would be possible to work out your bitcointalk username if you posted one of those addresses here (of course you could use a way to hide your ip).
So it would be possible to work out your bitcointalk username if you posted one of those addresses here (of course you could use a way to hide your ip).
The xpub is not transmitted to the electrum server.
AFAIK the electrum client is asking for recent transactions on single addresses (basically all used addresses + gap limit).
So the information it can retrieve is which address you send to / receive from, the time you send/receive and your IP.
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