The bigger question is why is every single western (at least) nation on this planet Israel’s little bitch?
EU
Anything EU related
Not every western nation... Ireland and Spain having something akin to a spine come to mind. To answer your question, though: economic and strategic military interests I'd say. There are individual capitalists making lots of money from trade with Israel and having lots of capital still translates to social and political power. The US, and I believe also the UK additionally use Israel as a military base for exerting power in the middle east...
If only people would vote according to their beliefs.
Even then: the German political system steers politicians towards compromise. Sounds good most of the time, but that means that whatever the beliefs of the politicians were when they were elected, they'll do different stuff all the time. And in order to stay sane, they convince themselves they're doing the right thing.
So voting can of course improve things a little, but we'll always see at least leftist parties moving significantly to the right after taking over government.
Weird how those compromises always go the way of rightwingers and billionaires. IMO, we wouldn't be in this situation if the compromises were between leftist parties and neoliberal "left" parties (e.g. Die Linke and SPD) instead of between neoliberal "left" parties and rightwing "conservative" parties, or just between various flavors of rightwing parties.