Also, if you've read more of his stuff you'd know he worked for a decade before he retired, saving up a significant portion of his income by staying frugal. He didn't just magically have two houses to rent out.
I'm not sure where the insane hatred towards renting out a property is coming from. A lot of the time the landlord doesn't actually make much money off of it. Even if the rent covers their mortgage payment (which it often doesn't), if something serious breaks or needs to be repaired, they're on the hook for that and may end up losing money on it that year.
No doubt much of his advice is correct, and all of it well-intended. But one has to be careful about advice from people in very different circumstances. They can get it disasterously wrong.
Landlords absolutely do make large, unearned amounts of money. Think about it for a minute: MMM is a finance expert, why would he put his money there if it didn't generate the best return. The idle rich (rentiers) in general are hated, but landlords in particular make additional money through sharp practices. The profession inherently involves (legal) tax avoidance, because a landlord makes a lot of their money through appreciation of their properties which is not taxed, and their rental income is usually taxed at a lower rate than ordinary earnings. Finally, while it's unfair to pin this on MMM, many landlords take advantage (wittingly or not) of their tenants' ignorance of their rights.
Finally, when a rich person says "it's easy to make money", it's a very small step from there to "the reason I have more money than you is that I'm smarter/more self-controlled/etc." Which is often a lie; often inherited privilege has a much bigger impact than personal qualities.
Not in the US. Rental income is income. I think you may be referring to deductions, which exist, but are not nearly as advantageous as taxing rental income at a lower rate outright.
So circumstances are everything, that part rings true. We're born into a good bit of that, and trained into the rest. From accent, to attitudes about race and religion we spend our lives accumulating advantages and albatrosses.
Sub-prime hurt the poor, since 2008 with QE we've seen the gap widen as more banker credit is created and flows into land prices.
Maybe. Or maybe they're spending their paycheck on things that they do need because they have to work for a living, they can't live by renting out their assets like MMM can. Example from the other branch: MMM can say "buy a bike instead of a new car" because he had the privilege of putting his "job" (rental properties) as close as he liked to his house. Most people don't have that option.