Racist?

I met my lawn guy at my house today to pay him.  We struck up a little conversation about how business was going and he mentioned that it was going very well.  He said he has even let go some of his "tougher" accounts that were always late on paying.  A couple of months ago we were talking and he mentioned a younger woman that he was having a real bitch of a time getting a check from.  Here is the breakdown of the conversation today:

Salty: So, how is biz going now?

Matthew: A lot better now!   I have actually picked up about ten accounts in the last 45-60 days.

S: That is great.  Hopefully they are all good accounts and not flakes.

M: So far so good.  I have even let go of some of the people that were not paying me on time.

S:  Like that bitch from a couple of months ago?  She sounded like real treat.

M: Oh ya, I stopped showing up to her house about two months ago.  Bitch, always had some stupid excuse.  You know who I refuse to take on as new accounts because they are the hardest to collect money from and will always rip you off?

S:  Single women?  SIDE NOTE:  This answer was given 100% because of the "bitch" who flaked a couple of months ago was a single woman and that is who we were talking about.

M: No way.  Not even close.

S: Oh ya, then who?

M: Mexicans!  I try to avoid doing work for them whenever I can.  Can't trust them.

S: Uh, I see......well.....um....

M: No, they really are terrible.

S: Well, um..........aren't you Mexican?

M: Ya, doesn't mean I don't trust those fuckers.  HAHAHAHAHAHAHAHA!  (Me looking down at the ground and just nodding).

S: I see.

M: Got to go, have another appointment.  See you later!  Trust me on the Mexicans.

S: Ok.  Talk to you later.

Now was he subconsciously telling me he was not trustworthy or was that some sort of under cover sting to see if I was racist?  What the hell just happened?  I then looked around to see if John Quinones or Chris Hanson was going to come out of my garage and scorn me for not correcting him.  Still confused.