Anyone who thinks you can’t get “real work” done on an iPad is nuts. Likewise, anyone who claims Apple’s tablet is not a real computer sounds like somebody arguing that the 1984 Mac wasn’t a real computer because it didn’t have a text-based command-line interface.
The iPad vs. Mac debate certainly isn’t new. Only the devices have changed.
I think that the folks making these arguments are jealous of the iPad Pro, or scared that it will become more important to Apple than their Macs. They want to use it instead of their Mac, but at the same time they’re unwilling to change anything about how they work. Instead, they want the iPad to be a touchscreen Mac with a detachable keyboard.