The Paisley club and Ross County both vetoed the proposals at Monday's Scottish Premier League meeting, which required a majority of 11-1 to take the planned changes to the Scottish Football League.
Gilmour, in particular, was the target of criticism by furious Aberdeen chairman Stewart Milne after failure to secure the required backing for reform at the summit at Hampden.
The Saints chief told the Daily Record: "Let all of them blast their shotguns.
"I'm still firmly of the belief, with all my heart and not letting it rule my head, that what I did at Hampden was the right thing to do.
"I still want to see elements of the reconstruction proposals - like a single league body - implemented. But not at any cost.
"First of all I'll tell the St Mirren supporters the reason for doing what the club did at Hampden."