This thing about what actually makes a keyboard mechanical has been discussed multiple times before; but, it is always an interesting aspect of our trade; truth be told, anything that has moving parts is by definition a mechanism, therefore, it is irrelevant if the mechanism includes rubber, steel or plastic parts; thus, by definition, all keyboards are mechanical, unless they do not have moving parts. Touchscreen devices that offer a "keyboard" are not mechanical, but even the vibrators some phones and tablets use to give the user some feedback of the typing action are mechanical devices, maybe the keyboard is not mechanical but the feedback mechanism and the software that synchronize it with the user's action is. Also, in some aspects, the screen's layers of capacitive materials that registered the input of the user are also mechanical devices, a flexible net is bended to record the position of the touch on it, that later will be translated into an action by a complex code sequence. Mechatronics plus Infotronics devices surround our daily activities.
This discussion will never end, however, mechanical actuators based on rubber components and those based on metallic and plastic ones make a different typing experience. Each group of users would like to think that they are using the only true mechanical keyboard and there is no reason to try to convince them otherwise, let each mechanical keyboard user to enjoy their devices, they earned that right when they decided to pay a lot more for their keyboards than those that decided that there is no reason to replace the stock rubber dome keyboards that came with their PCs. Do not let them to know that even the last are users of mechanical keyboards, a cheaper iteration yes, but mechanical at the end.
