I obviously can’t debate a Psak that has not been explained, but I think it’s important to make this point: People often use the term “Lashon Hara” as an umbrella term which encompasses all forms of forbidden speech, such as Ona’as Devarim, Motzi Shem Ra, Rechilus, Megaleh Sod, Malbin Pnei Chaveiro, et al. If the reasoning for the Psak was a technicality limited to Lashon Hara in its narrow sense (such as Apei Tlasa), then either the Shaila was presented incorrectly, or the Posek needs to do a better job of understanding Shailos. The question was not whether the particular post was Lashon Hara per se, but whether it was permitted to post.
In any case, to the extent that I am not being allowed to know either the identity of the Posek or the reason for the Psak, there is no reason for me to consider it authoritative, especially considering that it is at odds with my own understanding of the Halachos.
A new cycle of Chofetz Chaim Yomi starts today, so maybe this time I will figure it out…