People who say RPGs have to have "roleplaying" to be a RPG are perpetuating a common misconception because they are using the wrong meaning of roleplay given to the name of the genre.
People don't realize that the meaning of roleplay that everyone knows these days is not the same as the meaning of roleplay that originated both in the name and the genre.
There are more RPGs made that have no real roleplay (the one that everyone these days think about) than those that actually offer that type of roleplay.
The first game to create the name of the genre was Dungeons and Dragons (as everyone knows) and the name of the genre came from the 1st edition rule books from D&D, and D&D back then didn't offer any roleplay at all, or offer any tools for roleplay. Characters didn't have any social skills or attributes (Charisma was even only used to know how many henchmen a character could have), and the world/universe of D&D back then wasn't explored in a way to offer roleplay either.
Campaigns and adventures were all "go into this dungeon, survive at all costs, beat the traps/puzzles, reach the end and you will get treasures and loot. Rinse and repeat." There weren't people having in-character conversations, any NPC conversations or anything else like that. It was because of this that the term "hack and slash" was born because that was what you would do in the original RPGs all the way to the early 90's. This mean that for 20 years, there was no RPG that had the "pretend" roleplaying that people talk about today. That's 20 years and many 10's of RPGs released both in video/computer and tabletop format.
(More on the hack and slash will be addressed later on in this post).
The name "role-playing game" was not created because of the (other) "role playing" that's "pretend you're someone you're not" (as we associate it with these days), but about how the players are each playing a specific role in the campaign by using their characters.
Role-playing sounds much better than Character-playing and so the name was born.
Here's where the name for the genre came from, the first edition rulebooks of D&D:
As we can see, they explicitly make a point that each character (including henchmen and intelligent swords) is a role and how important that is. Role is pretty much a game's term in original D&D's rules. Actually, if you notice, the terms "role" and "character" are interchangeable and mean the same in all those times up there.
To add more weight to this position: The first RPGs were all Hack & Slash games. The first D&D rules were altered war miniature rules, the character sheets didn't have any skills or attributes related to roleplaying or social interaction at all, even Charisma was only used for rules on how many henchmen that character could have at the same time. The campaigns and modules were all about killing stuff and working out puzzles to get the treasure at the end, etc.
Only after 20 years of the creation of D&D (and RPGs) did roleplaying games start to have rules about actual roleplaying and proper world-building, and campaigns and modules followed the same trend. Some old players back then even thought that would be the death of the genre (or at least it would stop being as fun). The Hack & Slash days were (back then) considered the Golden Days of AD&D.
Excerpts from Dragon Magazine #146, June 1989:
Another excerpt:
It's true that "pretend" roleplaying is something that enriches the RPG genre, but it's not a requirement, and the majority of RPGs ever released in any format prove this, since the "pretend" RPGs are truly the minority even to this day. Saying that RPGs need roleplaying is excluding 80 or 90% of all the games in that genre, and that's just silly.