Agree.
As a productivity platform, choosing the only browser to support is harmful for Coda. And the underlying reason why Coda chooses Chrome, which is just the Google account, damages the image of Coda.
I thought the non-support for other browsers than Chrome is only during the beta period. However, Coda comes to 1.0 with the awkward situation. The deep dependency on google’s is the choice that Coda team made. But I think making Coda indepent on things from one specific company is more suitable as nowadays decenterization is more and more focused.