Garland was never going to be confirmed, the senate didn’t haven’t the numbers to get it done. Obama nominated Garland, as was his right to do so. The Republican led senate considered his nomination and chose not to confirm him. A Supreme Court nomination doesn’t equal automatic confirmation as 1 in 5 nominations do not get confirmed based on historical data.
The only gripe is that the senate didn’t hold the customary hearings, but the outcome was already obvious. He wouldn’t have been confirmed even if they held the hearings.
If a Republican President nominates a justice and a democratic led senate chooses not to confirm the nomination without a hearing, then that’s fair game at this point. McConnell set a precedent and it will eventually come around and the other side can benefit from it. When republicans cry about it, dems can point to McConnell and say “deal with it”.
The idea that the garland seat was stolen is just wrong, though. He wasn’t getting confirmed with the senate makeup.