In America yes. In Europe no, you can't project US law here.

For example the "We don't bake cakes for gay couples" is absolutely not ok here either.

There does seem to be a loophole for enforcing tracking ads as "legitimate interest" (i.e. not seeking consent) if you also offer a paid subscription without them, which is what a lot of German news sites seem to have shifted to. There was a recent court case in Germany however because a company got sued for not providing an option to not consent to everything that wasn't related to ads (e.g. analytics, third-party widgets and so on) and most sites seem to now provide granular controls even when they force ads if you don't want to pay. Note that they still have to lazy load the ads after consent is given in order to be compliant. I'm not sure if this way of forcing ads is compliant throughout the EU as it feels more of a gray area given that the site usually sends the full article and then gates it behind a consent modal on the client, i.e. there's no technical requirement to show the ads, just a sustainability one.

You cannot discriminate based on race, for example.

A major point of GDPR is that it basically made "do you agree to tracking? yes/no" a protected category as well.

Specifically, it requires freely given consent to allow tracking. Freely given consent is defined by the GDPR as consent that was given without any discrimination, rejection of service, or extortion in any way influencing your choice.

So no, you absolutely cannot discriminate based on whether users agreed to tracking or not.