I've had DNSSEC validation enabled for years and Google's services never broke for me. I don't think the problem lies with Google on this one, it's probably a bug in your resolver (or worse, your ISP may be intercepting DNS traffic to Google).
DNSVIZ is a bit unclear in this case. It doesn't warn that the initial delegation from .com to google.com is insecure, but it does warn that the delegation from google.com to l.google.com is.
Google doesn't use DNSSEC, unfortunately, so this shouldn't be a problem. If your resolver breaks on this, I think that may be the result of a bug or misconfiguration, because there's no DNSSEC to validate here.
I am "forced" to allow "our" domains to be DNSSEC because... an auditor suggested it as a possible improvement and some manager thought it a good idea to do whatever said auditor proposes.
The argument that absolutely nothing that the world relies on, is not being singed (google Facebook reddit Cisco MicroSoft etc) holds no clout with the believers, unfortunately.
