I know the examples I gave with Litvish practices were not meakev halachos that we ignore (if they were, I wouldn’t be Litvish). I guess they weren’t really good examples of retroactive minhag justification. The mashal to Chabad’s Sukkah issue was more as an example of having a shittah phrased as a chumrah, when really we all know it’s a kulah:
-We’re so strict on bal gaavah that we have no mikvah and make all our bochrim shave.
-We’re so strict with our learning that we never say korbonos
-We’re so strict with the kedushah of the Sukkah that we don’t sleep in it
They all sound pretty silly when you take a step back, in my opinion.