I saw your post the other day and didn't respond because I don't know. It's an interesting question and situation, but it's going to be tough to track down specific information and breakdowns of why Mississauga voters voted that way. It could be something as simple as Debs had a stronger ground game there.
Also those SC results look extremely suspect. I question the accuracy of any result giving the winner over 95% of the vote. In many ways, the Jim Crow south resembled a post-Soviet authoritarian regime in terms of voter suppression.
South Carolina had no real secret ballot until 1950, which likely amounts for most of why that state had Nazi-like majorities consistently in spite of everything else for so many years.
