There seems to be some internal consistently around Apple's naming conventions, whether you agree with them or not.I'm so incredibly disappointed in the 14" M3 MacBook Pro. There is NOTHING about that machine that is "Pro". 8GB of RAM in a pro machine is a joke, as is only being able to drive a single external display and having only two Thunderbolt ports. The 512GB SSD is merely "acceptable", which is fine in the base machine I suppose. What's aggravating is that Apple had to TRY to neuter this machine. This is better than the 13" Pro it's replacing, but just barely. I'm continuing to hold out for an M3 Air 15". I'm sure it'll only be $200 cheaper, but I'm not paying extra for the 14" non-Pro.
Let's look at the iPhone and iPad as examples. The iPad Pro is basically an iPad with extra bells and whistles (better screen, speakers etc). Same with the iPhone pro and pro max (which have added functionality like better cameras and promotion over the base models).
So by inference, pro refers to additional features, while max / plus denotes a larger form factor.
In this context, a MBP means a MacBook with extra features / functionality. Which is not wrong, if we factor in the added ports and faster processor.