It's not only complacency, although it is a large part of it. Some of the main issues here is money in politics, gerrymandering, the gutting of the civil rights act. In fact, the most central issue here is probably money in politics.
Democrats wouldn't apply this rule to search engines or email. Why? Because tech companies would flip out.
Democrats are free to vote ideology when it's a GOP ox that is going to get gored. And vice versa.