The 'it costs you nothing to have a buyers agent' argument would collapse as it should.

The investors doing a very large portion of the deals are professional in nature leaving lower risk of default or collapse. 

My guess is that they don't think you will have the ability to close so they want to get some $$ for their time/effort spent on you before the deal inevitably collapses. 

What contingincy fund is in place for that roof repair, water heater replacement, sewer main collapse, etc?

You have little reserves and if it collapsed the tenants would have to move out and you would not receive any income.

True, a correction or downturn or Armageddon may be coming, and perhaps it will be the day after any of us buy the next investment, but here's the magic truth:  the market's high point before the collapse was in 2007 --> by 2017 the overall market (stocks) had reached a level of DOUBLE 2007's high. 

Just had a sewer line collapse on a slab foundation. $10000 to repair.

If it goes unchecked the crack will widen, the wall will continue to buckle to the inside until, a few years later it fails and collapses to the inside.Rule of thumb is when you can stick a coin in the crack you have a problem.

Just had one collapse$10000 to repair.

However, this initial plan slowly morphed into "we're not gonna use cement for the support columns since the foundation is pier beamed..." to "now that we've removed the wall and put in support wedges (instead of jack posts) and nothing collapsed, we're gonna patch everything up."