I don't think that's the point. I think the point is that a lot of the rights many of us enjoyed for free were taken away as a result of the UK government's bargaining position during Brexit negotiations.

Brexit itself passed by a relatively narrow margin following an illegally run campaign from Vote Leave, and on the back of promises which have turned out to have been worth less than the buses they were written on.

However, the governments of Theresa May and Boris Johnson successively expected the EU to solve all of the UK's problems by accommodating their ridiculous red lines. The EU essentially held the same bargaining position from the beginning which was 'no single market access without freedom of movement', and the UK squandered an awful lot of time trying to convince the EU to change that position.

OP may have a different view, but although I don't blame the UK government for Germany's visa rules[0], I do blame the UK government for the fact that I am now subject to them, when I previously was not.

[0]: I'm not familiar with Germany's visa rules for British citizens. However, I do know that Russia (for example) operate broadly reciprocally - whatever hoops a Russian citizen has to jump through to get a visa for another country, citizens of that country have to jump though the same hoops to get a Russian visa.

The UK Government originally had an agreement with <Germany> that there were no visa rules for UK citizens visiting Germany. Just show your passport and you're good.

Then the UK Government rescinded that agreement, but said they might negotiate some new deal.

Ultimately they then decided to make No Deal.

Meanwhile the <German> government is just sitting there and staring and wondering what on earth is going on.

Ultimately it seems to me to be a British internal politics thing.

But making Brits subject to the non-EU visa rules, where before they hadn't been, that's totally on Britain.