Today you go out and there's a pigeon sitting on the branch over your car, you scare it away.

Your friend is like "what did you do that for, you have no evidence this pigeon poops on cars!".

Your [asdfasgasdgasdg] position is "this pigeon might be fine" the OP's position appears to be [or at least, mine is] "pigeons are probably going to poop on my car". You're saying his position is insubstantiated ...

It's the difference between treating Google as unique, and treating them as a member of a class of businesses. It's not insubstantiated, it's just a different form of substantiation. If all advertising businesses the OP has dealt with before were underhanded then your position looks to them like "today is unique, maybe the sun won't rise".

tl;dr you can substantiate a position based on general behaviours of items in a class, it's not necessarily wrong, and can be just a different model.