The flaw was clear, you cannot logically attribute the property of badness by merely stating that it should be excluded, that was the take away point. Meaning, you cannot state that universally something is bad (or attribute that statement to someone) in virtue of it being stated that it should be blocked/restricted/etc.
*This may been a relative/absolute issue, my argument stands if were are dealing in absolutes*
My example was such. Cake is "good" in a universal sense (note, I don't actually accept that we can really find "the good" but for the sake of this argument I will use the term) both evolutionary (at what point in time at least, as a vestigal trait it can be "bad") and in a social context.
You have not established that X must also be bad. This may be a problem of you not defining what type of "bad" you mean. Your edit may be closer to what you mean.
Bad for Y, not "bad" in whatever sense you mean bad. Producing the result that X is bad for Y, where Y could be a person, platform or product. Applying this to my example, cake would be bad for me (my opinion) but not bad in any universal sense.
So, if this is what you mean the argument is meaningless as it is obvious that for the individual claiming that X should be blocked, likely means that they feel X is bad for whatever reason. If you had defined what type of "bad" you were referring to, in this case bad as relative to the individual, the argument would have been fine (albeit pointless).
However, since you claimed that the resulting proposition was "wrong" (that porn is bad), I took it to mean that you were speaking in terms of absolutes. In which case all we ended up with were two opinions.