You're completely right, of course. In my experience, these generators usually explain what the generated code means, though. These records are a lot easier to read than they are to write if all you've got is a manual and a technical specification.
I haven't used any hosted mailing services myself, but I can't imagine their control panels don't have either an option to generate the necessarily policies for you or an extensive guide on how you should configure these records and why. These records are the only part of the mail ecosystem these hosted platforms can't manage (unless you also let them do DNS) so they're a crucial step of the onboarding process.
On generators, a lot of them left me in an uncanny valley. They were supposed to make everything easier, but didn't explain the basic concepts, so I didn't know the values to even put into the generator. After I nailed down some of the basics, the generators just started making sense.
YMMV. There's an infinite combination of mail hosts/servers, DNS providers, and record generators. Collating all that information the first time can be overwhelming, if DNS or email aren't an area of expertise, but I'm sure there's a low-friction path out there. A Northwest Passage of email security. I'd love to find it.
As for configuring a mail server, yes, that's definitely way harder. But these days, most companies outsource that to the likes of Google or Microsoft, until they get large enough to justify administering their own. There's exceptions to every rule, etc. etc., but every company I've worked at has either used G Suite or Office 365.
The result being: many companies have email services running, but don't have anybody whose day-to-day is understanding how it works and how it's secured.