It ain't wrong from my end?

I find a particular fault in a particular instance of a system.   A naysayer finds no fault in a separate instance of a system in their charge.   The problem is not at the atomic level so it's not spooky influence at a distance (aka entanglement).  Of course, two takes are 1) the circumstances that the two systems are operating under are clearly different, so understanding that difference might provide insight into the difference in circumstances might suggest where the fault lies in the faulty system and, of course 2) you are mistaken, there cannot be anything wrong with the system you have in your circumstance as there is no problem with the one operating in my circumstance.

To illustrate, I add a comment to a thread in the Logically Fallacious forum.   Later I, for purposes of vanity, wish to recap my achievement but there appears no means for me to search for my own comments, or at least a search using my user name does not resolve to a list of my one and only comment to date.   This is either 1) a missing use case in the design of the forum or 2) I as designer fail to see the necessity for a user to have their needs met or indeed have needs.   

So I petition in each case point 1 is justifiable while point two is not, but what type of fallacy are we operating under when responding in the second form please?