Please explain remote grades to me...

So, when I switch from local to remote grades and vice versa, it removes the remote grade and gives me a blank slate in local grades.

Why can't I color in remote, switch to local, and have the remote grade still be applied? It's like it's either or when I would like it to be simultaneous. Or am i just completely misunderstanding this.

You can copy remote grades to local then carry on from there. That is what I do. I start off matching cameras for multicam with remote grades on the full source clips before making multicam clip. I just do simple angle selection in multicam, flatten, copy remote grades to local, add a node so that my individual clip adjustments are separate from the remote grades.

It's like it's either/or

It's not "like" that, it IS that.

Just how things work. You can't have both.

But if you explain a bit about the end result you're trying to achieve, we can probably help you get there.

Think the OP is bummed that it erases rather than remembering the old local stuff. Doesn’t have to be that way. But as you said it IS that way.

Yes it is one way or the other but you can copy grades both ways and then carry on. If you just select of course you will loose which ever one you were on.