My take on that is they bring up the concerns addressed above: 1. Daisychaining to connect a multitude of devices, and 2. Using them and extension cords to increase the distance they can reach.
The convo here is, I believe, more about two levels of surge protection working against one another.
Sure.
Have you seen an “un surge protected” power strip lately though? So, if one were to need to extend, from the back of a UPS (surge only side!!) to something - do you use a surge protected one? or try to find one that does not have surge protection?
I have several. You can find non-surge protected power strips (or more appropriately, just power strips) pretty much anywhere. Walmart, Home Depot, Lowe’s, etc.
Or use a heavy-duty extension cord… 
Operating guidelines require a properly grounded outlet with at least 800 watts available. We recommend against the use of a UPS, surge protector, or power strip.
Unfortunately, because there are a large variety of products available which may or may not meet the needs for your Glowforge, we’re unable to provide recommendations on whether or not a product would be appropriate for use with your Glowforge.
I’m going to close this thread - if you have any other questions, go ahead and post a new topic.