Don't stress it. Molly is for high load situations like gears and CVs etc. Without the high loads the benefit of molly is minimal. No amateur telescope could possibly put enough "pressure" into the grease, either in the bearings or the worm, that molly would be of any advantage. If you can turn the gear train by hand then we're many many orders of magnitude away from where molly comes into its own. Think about it, in industry where molly is used the loads are in the 10's and 100's of tons (actually GPa) not kilos. Sure the thrust bearing see what you might think is "high-ish" loads when clamped, but they're static loads. Even if you used a stilsen on the locking nut you still wouldn't damage the thrust bearings, but you might apply enough pressure to make the molly work
Bearings in a mount are generally spec'd vastly under their operating tolerances. Personally I'd be dubious of the source making the claim that it was the grease, more likely neglect or contamination (spilled juice/coke?) IMHO. Ask a mechanical engineer, molly is used in these kinds of inappropriate contexts because the label has "Extreme" on it and that was the end of the consideration.
Molly wont hurt (good luck washing it out of clothes and stuff) but the loads are too low for it to be actually useful in any meaningful way.