Why does the president get asked how he feels about abortion?

It's not like he can make any decisions regarding the legality of it. Politicians on BOTH sides of the aisle use this as a hot on topic. Are we as americans too stupid to know what a president has control over, and what he doesn't? Or is this issue so emotional that people will use it to make their decision, in spite of the fact that the president can't control it? And I'm aware of the Supreme Court appointee argument, and BUsh appointed them, and still no victory over abortion...