Not sure, but it seems there may be a fundamental question being asked here. If I trust somedomain.com, does this automatically mean I trust advertisers on sai

Not sure, but it seems there may be a fundamental question being asked here. If I trust somedomain.com, does this automatically mean I trust advertisers on said website? In fact it becomes even clearer where the trust boundary lies when taking into account the fact that even somedomain.com is putting advertising decisions into the hands of a 3rd party. So, how far should the infrastructure of the web go in terms of assuming trust boundaries transcend the immediate trust and obvious relationship between end user and domain?