The fundamentals of the two parties.

conservative: doesn't like change
liberal: likes change

Extremist liberals will burn down their own house just for the mental stimulation of rebuilding it. Often practical concerns intercede - so they'll turn to burning down your house in order to rebuild it.

The problem with extremist conservatives is they'll just let everything rot. Something is broken? Well fixing it would mean "change" and they don't want any of that. Any conservative party always has the issue that it's really really bad at recruiting new worthwhile people without an external event or something forcing it to. Becomes weak over time.