[Nasrudith]

The servers are entitled to send what data they want. The client is entitled to accept what and how they render it. That is how the protocols work. The servers can block visitors who don't login or load the ads but that has its own costs as they often find them not worth unblocking and just stop visiting.

Given the security issues involved with ads as a vector, general abusiveness, and poor programming leading to memory leaks and insane waste blocking by default is wise.

Even big ad networks have been caught hosting outright viruses from lack of vetting. There is no right to a business model and they have no right to access client systems.