The hamburger is more for "better" touch navigation though. I know these devices work fairly good with standard hover type states now, but the UX could be argued to be better when optimized for touch inputs.

Sizing is another matter entirely, in which I would agree, yea a tiny hamburger menu on an iPad Pro is likely bad. We all have engineering budgets though and in the grand scheme of things, iPads are likely a small fraction of the visitor base for these sites, so I get it.

¯\_(ツ)_/¯