They have pointed out in 2016 and now that if the Senate has the power to block a Supreme Court confirmation until after the election in an election year, then they are right in doing so. If the White House and Senate are of the same party in an election year, then they are right to proceed with a confirmation.
The problem with that argument is that logic would seem to require one to extend the "no confirmation" argument back two whole years--maybe even four. What's so hallowed about an "in an election year"? If there's a Republican president but the Democrats take the Senate in the midterm elections, couldn't they reasonably say, the very day after the election, "Well, the people have spoken; they've elected a Democratic Senate, and so we're not confirming anybody until after the next election when they have a chance to speak again"?
I really wouldn't give anyone any ideas.

Only a little more seriously, you make an interesting point here in that I do fear we could see this exercise in power legitimately last two years given that the mid-term elections now practically seem to kick off the campaign cycle for candidates running for the presidential election two years later.
I'd hope to think that a president of the other party would put forth a moderate candidate which could get confirmation. But then that is exactly what Obama did with Merrick Garland, and we know how that worked out.
It also raises another interesting scenario. What if Hillary Clinton had won in 2016 and, to extend the hypothetical even farther, the Republicans had lost the Senate?
I believe the lame-duck Senate would have moved to confirm Merrick Garland with all due haste as a justice the Republicans could reasonably live with.
Now, if you think the hypocrisy arguments this year have been strong, imagine what they could have been in this situation. The Republicans, rightly and consistently, would argue that the people had spoken and therefore they were now proceeding to confirm the nomination placed before them.
The Democrats would be placed in a bind. They would be hypocritical in withdrawing the Garland nomination or voting it down after having talked it up so much. However, they clearly would have yearned to put forward a more liberal candidate especially if they had control of the Senate to ensure confirmation.
I'm thinking they would have risked the charges of hypocrisy and withdrawn the nomination anyway arguing that President Clinton had the right to nominate her own justice once she took office. Perhaps I am wrong. I do agree with Mr. Garner that this has all turned into a naked power game and looks to remain so for some time.