@Enri1804 I very much doubt any petitioning will make any difference to Airbnb's stance re their classification re infants/babies, but as we - these days - rarely have families with "babies" (and as a recent booking where we did accept a 2yr old baby still using a cot, and as several items and areas were left not as we'd ever experienced previously (ie Bedding; soiled. Walls; crayoned on. Floors and just about everywhere; covered in crumbs) we have taken a step we'd never expected, and have changed our listing to no babies!
TBH I'm more concerned about the ages that Airbnb perceive to be "children" (3-18) as whilst in one way that age range is encompassed by the word "children", in another way Hosts' are not being prepared for what might await them or their Cleaners when the Guests' leave.
Of course, there's always the case that not all children are the same, in the same way that not all of us adults are, so I understand that Airbnb might be loathe to create - shall we say - a 3-5yr age group; a 6-10yr age group; an 11 - 15yr age group; or a 16-18yr age group, although I think that Guests' would have more than a idea of what the children from those age groups would not only be like, but also Hosts' would have more of an idea as to what facilities to provide for each age group.
Except for acknowledging that not all Guests' read everything us Hosts' put on our listings, I would make certain that somewhere "prominent" in your property's details, you categorically state that the MAXIMUM of 8 (EIGHT) Guests INCLUDES any children AND/OR babies/infants - otherwise it's highly possible your maximum will be misinterpreted time after time yet again!
If you find that such wording doesn't make any difference, then the only way around the "problem" I could suggest is to use the wording I suggested above, but to include an extra charge for numbers in excess of the 8 (EIGHT), of a very exhorbitant amount!