Well, Recently there was an art post taken down for just having humans. This is the art that was posted: https://anegyhw-nsfw.tumblr.com/post/172205490679/these-shyguys-dont-seem-that-shy-to-mebrand-new (warning NSFW)
It depicts two Shyguys and was deleted for the following reason "Irrelevant to site. (Human only, skin color and masks won't count)" Which caught me off guard because normally Shyguys aren't considered to be humans due to two main factors.
1. We do not know what is under their mask, it could really be anything.
2. They are a member of the Koopa Kingdom/Browsers army both of which are only shown to contain nonhuman entities.
Those two factors lead to most people considering Shyguys to be nonhuman humanoids similar to most of their countrymen. Now if they should be considered human despite this, then why do toads get the free pass? They originate from a kingdom that contains humans, and it has been depicted that the mushroom cap is little more than a hat(Granted this was in a spin-off).
Personally, I don't believe that it is accurate to call them human as it is little more than an assumption while they are humanoid by definition. Now I'm not the one running this show and I would like to get a straight answer to prevent any confusion.
Updated by Furrin Gok