I wouldn’t complain at all! I am not a stickler for the ‘perfect’ thread. It’s good that people contribute.
So what if it’s derailed? In normal conversation, people go off on a different tangent.
I think being too strict on derailing shows that some people are OCD and everything has to be oh, so perfect!
Now if a member was insulting other members and being horrid to others in a thread … then Yes, l would complain.
Most threads get back on track anyway.
For me, this is dependent on context, and people disagree about context sometimes.
If someone starts a thread on their mother dying, and there’s a derail on poo jokes, some might say that’s insulting. Others might say it’s just conversation.
If it’s just a social thread for fun, then derails are part of the fun.
But if someone wants to discuss an issue but can’t because every thread is a giant derail, then there’s no point in thread titles or making up topics. You could just start every thread with Go!
I’ve posted on a board like that before. It’s fun for the people participating, not so fun for people trying to join in or discuss anything else. It’s also easier to make veiled insults and pass it off as fun.
I miss your threads Art, you used to start some wonderful subjects, serious and humorous that led to some great repllies. 
Am I hinting? 
Mags, Thank You for your lovely words… you always say the nicest things. You started some good ones too… l know your Covid thread just ran and ran and nearly matched Agatha Christie’s Mousetrap theatre run!
I have a puppy now, hence why l post less! Some days, l am inspired and think of some threads l could start but l know, once l log on here… my addiction creeps back in and l am still logged on until the day is nearly gone!
My late mother warned me about pulling threads. If I pulled the wrong one some clothing might fall off
