I'm not sure how 'not forbidding' is different than 'allowing'.
The AC said it better than I ever could.
Regardless, slavery wasn't handled just through the 10th amendment. Article 1, Section 2, Paragraph 3 specifies that slaves (i.e. people who are neither free nor indianans) count as 0.6 people for determining the number of congressional representatives from a state. Because of that, I'd say that the constitution condoned slavery.
You should actually research the matter rather than parroting poorly informed talking points. The 3/5th's clause was a compromise between the Northern States that wanted slaves to count for nothing (thereby eroding the political power of the slave holding states and presumably leading to a quicker demise for the institution of slavery) and the Southern States that wanted them counted at 100%. Had the North gotten its way it's quite probable that the Civil War and ultimate emancipation of the slaves would have occurred a generation sooner than happened in our timeline.
I've found that there are really no issues with regards to running a new OS for long periods of time. There was a time when regular reinstalls were a part of my regimen but that is long past. I reinstall only when there's a specific need. That doesn't mean I just put up with a slow computer either, I demand very fast performance from my systems. A reinstall just isn't needed to maintain that.
Likewise, components have gotten much better, and upgrades more incremental, so I've found the need to buy new hardware that would necessitate a reinstall to be less.
My guess? This person either has crap on their system that causes issues, or this is just a "magic incantation" they've always done for supposedly better performance without understanding or examination.
New York... when civilization falls apart, remember, we were way ahead of you. - David Letterman