You could also take the opposite spin on this: There is no secure internet access to begin with so why wouldn't you choose faster connection over more secure, but still compromised connection? Use SSL, TLS, SSH and the like where you need to be secure and assume that everything else is compromised. Why would one assume that their ISP is secure? Always assume that somebody is eavesdropping the connection, or running an active MITM against you, and consider if your mitigation actions are sufficient?
Would I consider TLS with SHA-1 to be sufficient for accessing Slashdot over potentially compromised network? Yes. In worst case my Slashdot account would be compromised, no big deal.
Would I consider the same to be sufficient for the company payment interface? No, I wouldn't.