Similar arguments would involve suing Intel for copyright infringement because their memory controller copied copyrighted information from RAM into cache. That's copying! But ultimately, Intel is just infrastructure; some user got the copyrighted data into RAM and knew full well that CPUs copy it into cache from time to time. That doesn't make Intel a party to your copyright infringement lawsuit, even though they did instruct the infringer's device to make a copy without your permission. It simply isn't reasonable -- no efficient CPUs could be manufactured if you won your lawsuit. So it's unlikely a court would hold Intel responsible.
Finally, there is the classic "if you read this, you owe me $50." You just did! But any court would find that an unenforceable contract because you didn't really consent to it. So I won't be suing you for $50. The world couldn't function if I could do things like this. So contract law exists without that particular contract being valid.
Also very weird is that the Canadian terms are dramatically different and don't mention this restriction at all. In fact the whole long list of prohibited stuff in section 3.II.B is absent, even though both countries' terms cover the Online Store service in which the US terms include this wording.
Given that, maybe the true cause of the wording is boilerplate wording from their US lawyers which their Canadian lawyers don't have in their boilerplate? It's not simply about Square Canada being less of a liability risk than Square Inc, as most provisions of the Canadian terms do have Square Inc as the contracting party.