But I want Democrats to acknowledge that they were also wrong to try to filibuster when Alito was nominated in 2006, and in general when calling the GOP on obstructionism to own up to and apologize for their own obstructionism in the past. Obama has mentioned he "regrets" the filibuster, which is a start.
I don't think it is necessarily wrong to filibuster a nominee who a significant portion of the Senate feels is unqualified. But can anyone tell me why Obama's nominee is unqualified?

The filibuster should be used as a last-ditch effort by a minority to pressure the majority in dire circumstances. (That's why I think a filibuster should be an oral one, where Senators have to keep speaking to keep it going, not this "gentleman's agreement" that you need 60 votes or you table discussion.

) But McConnell's threat to use it
before any nominee is named is simply obstructionism and an abuse of power. Which is why the Democrats had to remove it as an option for some regular business.
It also should be pointed out that the Alito filibuster never materialized, and that it was called for
after the Alito hearings. Democrats didn't unilaterally vow to filibuster whoever Bush nominated.