It's that simple.
There are lots of towns, villages and cities in Israel. But Jerusalem isn't just the political capital of Israel (that's a statement of simple fact), it is the cultural and historic capital of the Jewish State.
Jerusalem was and is the center of Jewish life. And of Judaism.
Refusing to recognize that Israel's government is based out of Jerusalem does nothing for any so-called "peace process" or "two-state solution". It's a refusal to recognize the existence of Israel. The refusal to recognize Israel's existence and Jerusalem have the same racist rejectionist basis.
Israel shouldn't exist, they believe. It exists. But its existence can still be denied. Every part of its existence must be treated as temporary and offensive, they insist. Israel's very existence is a gift that its people may one day receive if they prove themselves worthy by committing national suicide.
The only way Israel can earn the right to exist is by destroying itself.
It's not just the attitude of Muslim terrorists. It's also the attitude of their sympathizers, appeasers and enablers.
There is no future date at which the PLO, Hamas and the anti-Israel lobby will recognize Jerusalem. Or will accept Israel's existence. Recognizing Jerusalem is recognizing Israel. Refusing to recognize Jerusalem rejects Israel's existence.