I think people should worry a lot less about who is doing the nominating and just focus on who the nominee is. Souter, John Paul Stephens, Kennedy, and Roberts were all nominated by Republicans, and none of them wound up being great enemies to liberal legislation or social objectives. You never know how these people are going to turn out once they sit down on the court. Sure, this lady seems to be a female version of Scalia, but that's not all bad. Scalia was a great judge and his influence on the legal field can hardly be overstated.
I don't really buy the argument that the President has some duty to wait until the election is decided to fill the seat, and I also don't think the Republicans are being hypocrites by going forward with the nomination. They have the power, they aren't using it in a way that is counter to the Constitution, and to me that's just the end of the debate. Democrats should just console themselves with the knowledge that once the shoe is on the other foot someday they will do the same, and I think we all know the Democrats would do exactly what the Republicans are doing now if they were in the same circumstances. They weren't able to in 2016 because they didn't have the votes in the senate; if they had, Garland would be on the court instead of Kavanaugh and I don't think anyone would think twice about that.
I personally think the Republicans were out of line in 2016 by refusing to fill a seat for 8 months, but I guess the American people had a chance to decide whether it bothered them at the ballot box and it seems like it didn't (or at least it didn't bother them more than the idea of Hillary being President). Then again, maybe that's just indicative that the court is a bigger deal to extremists on either side and not that big a deal to the rest of the country.