IMO that is what it's like to live in Germany. I don't expect people to bend over backwards for me. But on the one hand, Germans absolutely insist on immigrants learning German, but on the other hand, even when you are learning German, they don't really change their behaviour at all, so actually learning German is far less helpful than you might think.
I encountered the same with another language. I think this is just the matter of practicality and efficiency, no one is out to impede me in some way. It's on me to learn the language and I shouldn't expect people to go an extra mile and babysit me. I don't deserve special attitude if I'm doing the thing that's anyway normal and expected.
Also, I don't say it's not difficult in your situation (though I envy you, wouldn't mind moving to Germany myself) but I suspect a lot of this can be projection. You feel like you are separated and people don't want to hang out with you because of the language and you behave accordingly, you hang out with a group of fellow immigrants, etc and this becomes a self-fulfilling prophecy. Especially if you are sensitive to rejection. You give more weight to every sign that a person may be predisposed against (even if it's their bad mood not you) and discount signs where a person is friendly.
But that said can also be bad luck with social circles. I have met people from different countries who are quick to profile and look down on foreigners and people from the same country who are open and nice.
I could talk at further length about it, but I guess I am not predisposed to do so, because it's clear you've already made your mind up, and it's not so enjoyable to discuss German society with someone who has no idea about German society and yet clearly has very strong opinions on it!
Also I don't blame everything on you, just pointing out you have agency, can change your social circles and find friendlier people, and feeling entitled is not always the best strategy ;)
All I will say is that I appreciate that I have agency and despite the difficulties I have outlined above, I continue to learn the language, and I continue to go out and engage with people of all sorts, and to generally live my life. So whatever picture you painted of me in your head, I think somehow it's not really grounded in reality. On the issue of my supposed "entitlement", I only hope to be treated in the way I treat people myself. I am not looking for special treatment, only treatment with some degree of the empathy you say is so important for me to have!
I suspect the GP is very well able to describe their situation accurately and to draw meaningful conclusions from it. In English speaking countries immigrants are treated so much more gracefully compared to Germany (or France, for that matter). You either are perfectly fluent or you may as well not bother whereas in English speaking countries people will be happy to adapt.
What else should native english speakers do? There's no way they could make communicating easier by switching to a lingua franca since they are speaking the lingua franca already. That leaves adapting as the only possible way to facilitate communication, doesn't it?
I think the point is that we have lots of experience doing exactly the thing you say you wouldn't do. And think absolutely nothing of it. It's just what you do, because it's being empathetic and welcoming.
I always appreciate people speaking normally, I can always ask if I didn't get something and it keeps me on my toes. Teachers/instructors or news presenters are there for easy to understand language, normal people are for real street speak
Insist back. Repeatedly.
Germans (usually) don't do this out of malice, they do this out of (in this case, misunderstood and shortsighted) kindness and friendlyness. They try to be welcoming and make it easy for a foreigner by speaking English, thus removing the language barrier. To them, speaking English is improving your integration, at least in the short term, because you can communicate easily and efficiently right now. If you just ask once to speak German, you will be ignored since it is assumed that you are just doing this out of politeness. It is, to Germans, perfectly acceptable if you then insist on speaking German nonetheless and point out that you are not requesting German out of politeness but a desire to learn.
But the default mode for a German will always me to speak English to foreigners, never German.
Speaking slowly and simply has a similar connotation of impoliteness. If you speak slow and simplified German to a foreigner you are (in a German's mind) pointing out their flawed grasp of the language, thus offending the foreigner. Better to "compliment" the foreigner by speaking "normally", thus pointing out the foreigner's competence...
All the best!
I agree I should watch more TV and listen to more radio. But I don't even do these in my mother tongue, so there is twice the impediment.