My first book is self published. The publisher I used call themselves a subsidy publisher. They have an acquisitions department, are very selective about the books they choose, and accept submissions without an agent. I had read about the near impossibility of getting noticed by an agent and published by a traditional publisher in multiple articles and blogs. So their claims to be an innovative publisher changing the publishing market were intriguing. While I was deciding the best career path to follow, I sent my manuscript to them. They loved it, and gave me the hard sell to publish with them. It seemed too easy, so I asked a lot of questions. Because they are one of the largest publishing companies, they assured me they could give me more options and exposure than a traditional publisher. Of course, they couldn't predict sales or give statistics, but I understood there's no crystal ball in this business. Since then I have realized, marketing my book was completely my responsibility, noone gets rejected by this publisher, and everyone in the industry considers my book self published.
I've sold close to 900 books from personal book sales, book club discussions, and in the marketplace. That's small scale, but not bad for self publishing. Just not big enough to get attention from anyone in the traditional publishing world. From your blog it seems self publishing is a negative mark against me for future traditional publishing? It's impossible to know if agents are passing because they aren't interested in my second novel or because of my previous publishing faux pas. I just don't want to waste my time. If the vast majority of agents will pass on me, even if they really love my next novel, should I even send query letters to agents? Should I just self publish on my own, use the platform I've already started to build and sidestep all the rejection?
You don't have to mention your previous run in with the brutal reality of a company earning money by selling snake oil to writers. You query as you normally would. You simply don't say "this is my first novel."
Agents are passing because they aren't enticed by your novel. You must have missed the day when I mentioned that agents are mostly rapacious sharks who will eat their siblings to get ahead in this world, and if we think a book will help us make money we are going to pounce on it like it was a seal in a salty sea.