I am not at all surprised there was a huge response to that store's offer of training. You likely won't hear anything of this on CNNMSNBCFOXCBSABCBBCNBC; there is an entire subset of liberals that believe in and participate in gun ownership for self defense. Commonly, these citizens adhere to the left wing party line in everything except gun control. Many of these people believe that if they want to retain their alternative lifestyle, they must be prepared to defend it.
I came across this fact about a couple years ago while in a local gun store shopping for reloading supplies. After I had chosen my components I was wandering around the store to see if I wanted anything else. I bumped into a local 2A advocate with whom I am acquainted, along with 3 people he was helping to choose personal arms. These 3 were all transgender. I became curious and stood by to listen in, I learned that this advocate was giving classes for not only these 3, but dozens of other people in the alternative society.
I had a chance to talk with Mr. 2A a few months later. He told me that there are "underground" 2A organizations within the LGBT community all across the country. Many in these groups are terrified of "coming out" to their liberal friends as 2A supporters. Some who have let out the secret have been hounded, threatened with death, and beaten for not toeing the leftist line. But they are determined to never be victims and to take responsibility for their own safety.
I applaud them.