That thread was more about the fact, that it’s really disappointing that the m+ meta is looking like it will be the same as in BFA. With the latest disc nerfs it seems like resto druid is looking like the strongest m+ healer, and holy priest is looking to be on the bottom followed by resto shaman. It seems like blizzard has done very little to address m+ healer balance.
This thread is about a specific issue with holy, which is the spec is punished for dpsing, more than any other healer which is a serious weakness going into higher keys. Fixing that would not make holy stronger in raids, it would not make holy op in m+, but it would make it better in M+