Why do Liberals always deflect and never answer simple questions?

Like say you point to an actual, documented, irrefutable fact that exposes something in line with the Liberal agenda, they will ALWAYS react in one of three ways

1. Ignore completley

2. Deflect to something totally irrelevant

3. Straw man to the extreme

Its like, pathologic with them and makes sensible discussion absoloutley impossible. They have no facility to rethink their standpoint unless told to do so by MSM