That is indeed the case in some scenarios, but there are also threads in which I am completely unable to "like" posts -- the button doesn't do anything.
I haven't been able to work out what the defining characteristics of those threads are, but it seems most likely to affect hotel "review" threads and/or threads in which I have posted.
When there is a hotel review post in the thread, the software blocks the "like". Why? I don't know. Irritating? Yes.