Because they are complicit. The two parties are not the same, they differ on a few dozen topics, of which the public is acutely aware. For the other 1,000,000+ issues, they are either in agreement or are complicit in Republican ideology.
I think it’s a valid argument. For example, if someone wants to read Shakespeare but they aren’t a strong reader, you could provide a simpler version, while acknowledging it isn’t as originally intended. It allows for accessibility for a larger audience while not changing the experience for others. You wouldn’t tell someone to read a different story genre instead. This isn’t tools, where we have to bend the laws of physics, it’s changing some numbers in a database, and something already done for higher level difficulty settings, so just allow a version that is easier. No one is forcing anyone to play it that way.
I don’t fully buy into the ‘both sides are the same’ argument. I do believe the two parties are not different enough though. Basic shit like universal healthcare, civil rights, taxing the wealthy by closing loopholes, etc. should be what the left is doing in my opinion.