'Liberal' in this country is following the usage in the US meaning 'not of my political tribe'.
That's wrong on both counts. That's not how it's used in the US, and that's not how it's used here.
In the US it means socially liberal or progressive. Here it generally means centrist, although that's obviously not hard-and-fast.
There are many people - mostly the socially liberal or progressive - in the US who wear the term with pride and would, in many cases, probably get on with many of the people here who use it pejoratively.
I've never seen it used as a catchall for the "other" politically.