The whole world had to shift online with about 2 weeks notice, so I'll forgive them that. At the time I was kind of impressed to be honest that red tape didn't bring the govt machinery to a halt and that they were actually able to improvise a bit. But yes Zoom is not generally the platform I'd want them to use.

There were better alternatives and they had more time than that (when lockdown was possible but not enforced) to prepare.

IIRC the French installed gov controlled Jitsi server. That plus a VPN would be a whole not more secure.

If you do not have things in place I think "we need to discuss state secrets securely" would have been clearly sufficient to justify an exemption to lockdown rules.