Most liberals fight for their freedom. E.g. trump supporters who were worried that the left wants to ban Christmas, probably identify with at least some “liberal” Agenda. Most of the left might not be communists but have a focus on freedom on the social scale. Enabling everyone to have a good life and most freedoms but limit some freedoms to protect the system from abuse. E.g. you are free to start your business but your business has to have safety measures to protect the worker. Less freedom for you, and even your workers, but a better life for the workers too. A extrem liberal might hold the position that you should regulate businesses as a poor work environment would lead to people working somewhere else and the business failing to produce the product and through that regulate the market better than with laws that might have loopholes.

In other words, there is a fundamental difference. They might support the same ideas once in a while but their motivation is different. Usually the leftist actively believes the market won’t regulate itself and therefore fails to produce the regulation. As leftist think is a flawed idea, saying that they believe in said flawed idea, is kinda insulting to them