When Senator McConnell took his decision, it was not at all clear that a Republican would win the 2016 election. The odious Hillary Clinton was the presumptive nominee of the Democratic Party, though Bernie Sanders was still making inroads, and Donald Trump was throwing the orderly Republican nomination process into chaos. Every poll, every poll, concluded that Mrs Clinton would solidly defeat Mr Trump if that was how the November contest would be held. If that turned out to be the case, the (purportedly) more moderate Judge Garland would be replaced as nominee by a really flaming hard leftist like, oh, Judge Ketanji Brown Jackson.
Even if Mrs Clinton would simply have renewed the appointment of Judge Garland, were he on the Supreme Court he would have voted to uphold Roe.
Senator McConnell placed a serious bet, against the odds, and he won; he filled an inside straight, when the safe bet would have been to fold.
I’m very proud to say that I voted for Mitch McConnell in November of 2020!