Because you have no idea what BBQ is the shit you have described in grilling and any monkey can do that. There is a difference as there is nothing better that REAL American BBQ clearly you have never had it. Slow smoked ribs, brisket, chicken etc smoked low and slow with indirect heat for hours with hickory or some other hardwood and yes beans are a side dish. Here is some from a BBQ place I went to awhile back. The color of those ribs shows that the smoke has penetrated into the meat and left a bark outside. It is fucking amazing. Behind it on the bread is some pulled pork.
https://teakdoor.com/images/imported/.../XaYQ3ZX-1.jpg
This is some my lady did on our home BBQ with hickory. It ain't fucking the grilling you talk about that isn't BBQ. Not to us Americans.
https://teakdoor.com/images/imported/.../6VOgw5p-1.jpg
https://teakdoor.com/images/imported/.../jmetr5t-1.jpg
Not as pretty as the pro stuff above but smokey and amazing in the flavor packed into that.
In summary you lot Grill you do not BBQ and yes beans are a part of it and it was so way before the limeys bastardized them into a breakfast food.