Never heard of the pollster. Race remains a tossup until proven otherwise. Michigan polling should be taken with a grain of salt anyway.
I agree with much of what you said, and Whitmer isn't winning by 10, but this poll still shouldn't be totally disregarded, and it's pretty clear Whitmer is not doing that badly at all. Also, if this doesn't qualify as proof that the race isn't a perfect tossup, I don't know what does.
What I'm saying is, a Whitmer+10 poll shouldn't be taken seriously, and the bigger the lead for one candidate, the truer this is - but it also means that candidate is likelier to actually be leading, as is the case in this poll unless it's very wildly off the mark (which it might be).
The Craig internal has a tie at this point, and by adding 6% to early support for an incumbent one gets about a 52-47 win for Whitmer. Incumbents usually show why they won the first time.
Frankly, where did I say I disagree with that assessment? (Though as a sidenote, I think Whitmer's margin, if she wins, will be smaller...probably no more than 3 points.)
