Our concern was not that our contribution would be GPL licensed, our concern was that we didn't have permission under GPL to distribute the contributions even if we were fine with them being GPL licensed. For details as to why we were concerned, see https://www.gnu.org/licenses/gpl-faq.en.html#GPLPlugins - for any company that should be a clear signal to stay away.

An employee of a company saying it's fine in an email is also not issuing another licence. We did suggest they use another licence than GPL, which they eventually did after months of arguing with them that just saying "it's okay because we don't care" makes no material difference to us and that GPL does not unambiguously provide us permission to do what they want us to do.