Really? How does that work?
Are you telling me that a 50-year-old man with a clean licence for 30 years would pay more in insurance for a 125cc bike than they would for a 750cc sports bike?
And if you think it's justifiable to pull somebody up because you can't see their face, then I think I'm going to have to respectfully beg to differ, and ponder as to what bloody country I'm in. Mind you, I've done a lot of that recently.
So you would therefore agree to not checking on any bike, what license the operator holds? With multiple different options, for multiple different bikes, across multiple years. It's not simple.
You can't really ID or age check the rider without stopping them.
Same as a 50 year old man would pay more to insure a corsa that is regularly driven and crashed by 17 year olds than a big more powerful Volvo than is driven generally by more mature people and involved in less incidents.
125s are more likely to be stolen, and more likely to be involved in accidents, it makes sense to have a higher insurance cost for them.
I insured a GPZ900R for £120, to insure a 125 for pottering around town they wanted closer to £300. The situation isn't unique to me, and many other motorcycling friends have found the same with quotations.