Easily defeated argument. If that website doesn't want members of the public accessing it (and picking and choosing what parts to access), then don't make it publicly accessible.
This is not necessarily a good counter to that argument.
You're assuming they don't want the general public accessing the website, perhaps they do and would also like the revenue that comes with the ad's served on the site, because that is, broadly speaking, how the ad funded model works.
I personally think ads are a terrible model but a paywall is an entirely different business model with different considerations.
They are publicly hosting their content with a protocol that was designed for clients to only follow the links they are interested in.
Rather than gimping the browser stack for everyone, websites should use the tech they already have. Like rendering ads directly into the page contents.
No it isn't like stealing at all. HTTP and REST API was explicitly designed so that clients can request and explore only the links they are interested in.
This includes links to tracker filled javascripts and images hosted on ad servers.
You're assuming they don't want the general public accessing the website, perhaps they do and would also like the revenue that comes with the ad's served on the site, because that is, broadly speaking, how the ad funded model works.
I personally think ads are a terrible model but a paywall is an entirely different business model with different considerations.