Is OTHER wrong in the post ? POST : Am I the asshole for joking about my GF’s parents being involvement in MLMs?

So I’m 18, and I’ve been dating GF for over a year now. And while we’ve been dating for a substantial amount of time, there’s still a lot I don’t know about her family (especially her parents) because they don’t fully support our relationship nor do they care to know much about me. 
(That’s another story within itself but nvm for now. My relationship with her folks is 
semi-friendly)

Anyways, I’m on YouTube and out of random curiosity I decided to look up my girlfriend’s parents because I know they make YouTube videos for fun. I honestly expected to find some embarrassing family videos about my GF and maybe some clips of family reunions or something. I don’t really know, I was just bored. I ended up finding her mom’s YouTube account and while I’m scrolling through her old videos I See a thumbnail with GF’s mom holding up
A bottle of vitamin supplements and essential oil‘s. 
Now, I don’t know much about MLM’s, in fact the only times I hear about them is on Reddit’s r/antimlm so already my opinion of their business practices are bias. I click on the video and sure enough it’s of GF’s mom trying to convince the viewers that they need to invest in her MLM. I found it funny because her mom has always seemed like that type of person to push an MLM and get sucked into that type of industry and I could imagine her shamelessly promoting these products to everyone. 
So, I’m checking out a couple other MLM videos made by my GF’s mom and at the time I laugh and think that this will be a funny/lighthearted Conversation to talk to my girlfriend about. 
Boy, was I wrong...

My GF ends up calling me while I’m going through some other videos her mom has made, and eventually we get to the subject of her mom’s MLM videos. She tells me that she’s familiar with their business practices and that they’ve actually made some money from it. 
I joked around saying that “ it must be hard for them to sell miracle tonics in this Day and age” because in my head, essential oil‘s are a complete scam in regards to what they claim to do for you. I go on to joke about the shameless marketing tactics I could imagine her parents pulling in order to sell their essential oil‘s (Sharing it to every one they know, and putting it on all their social media’s etc).
GF realized that I was making fun of her parents and their MLM and she shifted into a more hostile tone. 
Realizing this, I back off and say that I’m only poking fun because I’ve heard about the more questionable side of multilevel marketing businesses, but she wasn’t having it. 
My GF told me that she’s 100% positive that her parents I have made a lot of money from these companies and that a lot of her childhood was centered around her parents pushing these products (essential oils, etc). 
I didn’t know that she felt so strongly towards the subject and I begin to genuinely apologize for hurting her feelings, When she hangs up on me.

Am I the ass?