This skit is an interesting cultural milestone. Monty Python was funny but, for the most part, ridiculed conservative British society. They did not ridicule much that was on the Left. At the time, this skit probably was not viewed as political or taking a stand against liberal pieties. When you hear the remaining Monty Python crew today in interviews, they are definitely liberal but you can tell that they are not comfortable with modern radical liberalism and cancel culture.
Yes, they are liberals. So were most Dems prior to this century. We disagreed with them on many issues, but fundamentally we agreed on our basic founding principles - individual freedoms like free speech, freedom of religion, etc. There are few liberals left today. The Dems of today with few exceptions (looking at you John Fetterman) are no longer liberals. They are self-identified progressives (another misnomer). Probably it’s best to quit calling them liberals since they are not. Radical leftists fits better.