No scientist can choose to believe something is true because it favors the left-wing agenda. Or the right wing for that matter. It's the definition of un-scientific thinking.
Now, some topics are extremely charged and one has to be extremely careful on how to present the data not to stir the nest of hornets in either direction.
Scientists are no different. If falsifying results or avoiding certain research areas is what is needed to keep your career - and stay alive - then that's what they will do.
It's not a new phenomena, see e.g. Galileo. Arguably the most extreme case of this was in Stalin's Soviet Union, hence the term Lysenkoism (https://en.wikipedia.org/wiki/Lysenkoism) for "deliberate distortion of scientific facts or theories for purposes that are deemed politically, religiously or socially desirable."
We are thankfully nowhere near the extremes of Stalin's murderous regime. No one is going to put a bullet in anyones skull if they publish anything saying men are better than women, or anything about "race". But, if they do, regardless of if the research is absolutely perfect, there is still a definite risk to employment. How many institutions or companies would employ someone controversial? How many people would self-censor to avoid the controversial? Water down what they found etc? In general risk what puts bread on their table? For my money, if that doesn't limit the spread of ideas and search for truth what does?