A nice observation.
Indeed, being bound by NIS2 on the customer side comes down to their sector and their size. In turn, a supplier (such as ourselves) will typically be pulled in by contract.
So there are certainly commercial decisions at play. Namely, should we respond to this questionnaire and put the time and resources into it?
I think that is the crux here, surely: we have to make the call, for ourselves, on the importance of the business relationship over this one response.
A very straightforward call, perhaps. And no different from other supplier decisions.
Either way, thanks for raising the issue.