It's not saying that at all.
It might be somewhat like F1 if on the one hand you hand semi-autonomous fast cars and on the other hand you had stock Toyota Corollas, but that's still not a good analogy because it treats the issue backwards and in that scenario no amount of driver skill can really ever compensate to compete. I'll tie this back into F1 at the end in an analogy that isn't about the car (because the "skill" that is add-ons isn't giving you a new "I WIN" button).
Add-ons don't raise the ceiling of play, they raise the floor. Basically by saying the base game obfuscates critical information, the add-on processes these complexities and presents it to you in an easier to comprehend/easier to see/easier to react manner. It's still possible to play perfectly without add-ons––you can still be a World First Mythic Raider without them, hypothetically––but add-ons simplify the game.
I'll paint a quick example: Little Tommy uses the base UI without add-ons. His DPS is bad because he doesn't know his rotation and pushes things mostly at random anyway, he stands in fire on the regular, and struggles to follow LFR "mechanics." It's okay though, because he is good enough to level to 120, hit all his factions, probably do heroic dungeons, might find some success in Mythic0 groups, and whatever the rest of the content is this expansion.
Big Tom, on the other hand, uses all of Sco's custom add-ons. His DPS is a little above average because the game tells him which ability to use next (though he's still slow at pressing it), he still stands in some fire but usually move out of it quickly, and can do a good job with normal "mechanics" and might even make it through some heroic raiding. He's never going to be a Mythic Raider, but he's a solid enough contributor in some low/mid M+ keys, stomps through the leveling process, laughs at heroic dungeons, and runs through M0's with ease.
The way you set up the game to present information to you is huge. It's possible for great players to do well with poor/stock setups (I've seen it across many games), but for the average player it's a huge boon. Most of those World First Mythic Raiders are heavily leveraging Add-Ons and it's not for quality of life. You still have to push some buttons, play the game––like your F1 driver still has to drive the car––but you outsource a significant chunk of the information processing––like your F1 driver has engineers and a Race Director guiding him along to varying degrees––and that's just how the game goes. Drivers who are given good advice over the radio and are coached well in the moment are typically going to have better success than drivers who have no radio communications at all. The same way that F1 regulates the advice a driver may receive and from whom, the Add-On API isn't a source of infinite power – because at the end of the day, the driver still has to drive and execute his teams' instructions, and the WoW player still has to play and push the buttons.
