however no one is immune to criticism or being questioned
I am not saying that either. Everyone should be questioned if thing looks wrong but in this case I do not see much wrong here. I tell you what I have even given merit to only an image that was posted or a gif coz I thought it was merit worthy. I liked the joke and the humor presented on that. I am sure a lot of users will disagree but sending merit really is very much depending on someone's own view.
There are some members who are glaringly under-merited and sometimes I've looked back into their post histories and sought out posts to merit. Not saying that's what Dabs did, but who knows. All I know is there's not anything about what he did that would lead me to think he's a merit abuser.
I have done this too several times and in regular eyes it may look odd but the one who awarded it he/she must have an explanation and they are right in their point of view.
In Dabs case, I am sure he has some good intention and logic and looking at the merit sent in two WO posts, I would say that I would do the same if I had sMerits and spotted it when I was in a good mood.