It's not as true and there's actually been studies on the particular voter behaviour in 2016, and belief in 'fake news' (as in literally made up stuff) was a strong predictor of defection from the Democratic to the Republican ticket, and there's solid psychological evidence why this affects conservatives in particular[1]

It's also very trivial to see if you eyeball the size of the market for misinformation. While there are some highly partisan left-wing media in the US, and there were some facebook pages targetting say, Bernie voters it paled in the market for the Trump base, literally by a magnitude or so in revenue. Which I think is very obvious too if one looks at the size of the audiences of youtube channels attracting those audiences or people like Alex Jones.

NPR in 2016 actually did an interview with one such 'entrepreneur', who actually tried to sell fake news to virtually everyone, but had very little success with liberal audiences.[2]

[1]https://www.theatlantic.com/science/archive/2017/02/why-fake...

[2]https://www.npr.org/sections/alltechconsidered/2016/11/23/50...