I don't get your point. DNSMasq doesn't ship with a client, because it's a server. It's a cacheing resolver and a DHCP server that is usually run locally. I don't know of any system that doesn't come with its own built-in (or standard) DHCP client.
His objection is that it doesn't replace the use case that resolvd is supposed to solve. Which is to provide a local service that can redirect DNS queries dynamically as local interfaces go up and down, which is where the integration with a DHCP client comes in.
Makes sense; a lot of the systemd ecosphere seems to be about hotdesking, plugging things in and unplugging them, moving from one wifi AP to another, hibernating and so on. I don't encounter these use-cases, on the whole, which is probably a large part of why I find systemd so annoying.