All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
There is no doubt that merely leaving such messages – and not deleting them – is not Kufr. If relating Kufr does not constitute Kufr by itself, then how is it that merely leaving messages that include Kufr would constitute Kufr.
Ibn Muflih said in al-Furoo’:
“A person who relates Kufr that he heard of and which he does not believe in does not become a Kaafir (disbeliever); perhaps this is a consensus among the scholars.” [End of quote]
Therefore, what you are asking about stems from whispers, so you should avoid them, ignore them, and strive to treat them.
For more benefit that reporting (narrating) a statement of disbelief does not make one a disbeliever, please refer to Fatawa 352756 and 91710.
Allah Knows best.