100% should be disqualified.
Let's go back to 1976 when James Hunt was going for the championship with McLaren. The car was disqualified for being 0.1cm too wide in the wet stripping him of a race win. Harsh but 100% fair providing that the decisions remained consistent.
I think Hamilton should have been DSQ on the basis that the rules were broken, clear or not, they were broken. 1 win wouldn't affect Hamilton at this point anyways. The championship has been a blowout of boring processions with mostly 2 silver cars in the top 2.
I bet if Ferrari had won and was down on tyre pressure then they would have been DSQ but who knows because that didn't happen.