Aioli, by definition, is ‘garlic and oil’.
Mayonnaise, by definition, is ‘egg yolks, beaten with oil.’
Mayonnaise and garlic is therefore, by culinary definition, aioli.
I invite you to ask any French chef.
Aioli is “garlic and oil” by translation. By definition aioli is a spread made from oil emulsified with garlic, which mixing garlic into mayonnaise does not achieve. That said, the colloquial use of aioli to refer to just about any thick smooth spread is well on its way to changing that. Pedants like me can fight it all we want, but languages evolve. It’s just what they do.