@Rafael Davis
I don't know about all states, but here in Texas, a listing agent is required to submit any written offer they receive to their client. Even if they've given instruction to not present anything below a certain amount, they're still required to notify them of the offer. Just like any field though, the will be people good at their job and others who are bad at their job. You could file a complaint with the licensing board if you really wanted, but you'll probably make a bad name for yourself that way.
I once made an offer to a broker on a reo going up for auction. I was a realtor at the time (only held license for a year). He was on the board for the bank and insisted they wouldn't accept my price and said he'd have bought it himself at that price (owned MANY rentals here). They accepted my price and he asked me to move my license under him.
I've encountered quite a few realtors who say something can't be done or is illegal, but they just aren't correct. Investors tend to be better informed on a lot of real estate aspects. When my wife and I bought our current home 2 years ago. We had a realtor quit answering our calls or replying to or emails because he thought our offers were too low. I contacted another realtor with two offers to submit (one was his listing, other was as buyers agent). He waited a day and then said he wouldn't work with me. Third realtor I started working with different when have to show me or house because the first one had already shown it and wouldn't respond. She wound up getting an easy commission and we negotiated the price after the LA said the price was non-negotiable. You've got some good ideas here on how to proceed. Find an investor friendly agent to use.