Wrong, they pay attention when people pay them or threaten their pay.
I know, actually picking up the phone and making a call is much more difficult than making snarky, cynical comments on HN, but it's more likely to accomplish something.
If you care enough, you could even get out there and do something like work on the campaign of a primary challenger, or donate money to Amnesty, or anything else out there in the real world that requires time/money/effort.
No, they will become the lobbyists, consultants etc. There are so many openings for former congresspersons that they don't need to fear unemployment.
So it's not like there is a strong fear of being voted out, if you can grab even better paid job(for most, not fore all).
They are pretty comfortable with the idea that most people do not care about these issues. Civil rights are a side show for the majority of voters.