"Basically, a source of opinion and ideas with a political agenda."

This is exactly right, I think.

y, I find extremely troubling that:

Groups can so easily attack and label other groups as extreme when they hold similar views toward the other end of the spectrum.

Accuse others of being non-accepting of their ideas while at the same time not being accepting of the other groups ideas and beliefs. And willing to destroy the other sides careers and businesses over it.

People should always be able to have their own beliefs and speak out and question things without fear of persecution.

Being accepting and open to ideas and discussion is the way we should debate and express our ideas/opinions.

If you are having to spread and enforce your ideas through fear you are probably on the wrong side.

that's pretty easy to explain: liberalism is grounded in inclusivity, and conservatism in exclusivity, which is a tension that lives in each of us. and from a young age, we are educated that sharing and caring for others is good, and being selfish is bad. we tend to equate things that are good with being correct.

note that progressivism doesn't lay on this spectrum at all, as it only advocates progress over stagnation (a different facet of conservatism).

the philosophical positions of these ideologies are different from their political implementations, of course.