They have more skin in the game then you do.Make sure you get clear title.

They'd have to prove that the reason you denied them was for a protected reason, and unless you have a history that can be proven of rejecting a certain type of applicant, or you blatantly told them you don't rent to "their kind" and they recorded it on their phone, it would be hard to prove.So, as long as the reason for denying them is never because they have a kid or too many kids or the color of their skin isn't like yours or they have a service dog or whatever, but the reason is because they didn't fill out their application completely or they were rude or smelled of cigarette smoke and you don't allow it, or they didn't show up on time or give you documents when they said they would - you're fine.

You are developing thick skin.2.

It's important for your mental health that you don't let things like that get under your skin, you run a biz, just like a grocery store will have to toss some expired food, you'll have some losses.

And, if someone discounts good advice based on silly things like where they were born or the color of their skin or how long they've been investing - doesn't change the fact that it was good advice.Just sayin. 

Yes people can raise money without their own cash, but would you give your money to someone with no skin in the deal or significant track record?

In the real world, you don't get to buy properties without any skin in the game. 

As @Charles Press says, there are many ways to skin this cat, and many reasons.  

I am a chef by trade, so have a thick skin.

I think you also have to be someone with pretty thick skin to deal with longer-term tenants.