My question which perimeters will tell them the addresses belongs to the same person, if it's not the IP history or master public key? In a HD wallet I can not even tell two addresses are from the same wallet if the address formats are same.
Let's say you have created an HD wallet and have generated 20 addresses.
For getting the transaction history of these 20 addresses, electrum sends them to the server and the owner of the server will know that these 20 addresses belongs to the same person.
If you want to protect your privacy without using your own server, you should create a separate wallet for each of addresses, connect to different servers and use a new TOR circuit for opening each of wallets.