Isn't it the role of the loyal opposition to oppose?

Both parties make disengenuous appeals to bipartisanship.
Why do they insult our intelligence?
It is the role of the opposition to oppose.

When your favorite political party is in the majority, you fully expect them to press the advantage and advance the agenda that you voted for.

When your favorite political party is in the minority, you fully expect them to thwart the agenda of the other party do you not? You certainly cannot expect them to sell you out after you cast your precious vote for them.

So what is this nonsense about bipartisanship.
Is it not the role of the opposition to oppose?