Evan, for as long as you have been on the board, you seem to be looking for validation and approval by your peers to minister as you believe God has so led you to minister. Let me say that if you prayed about the type of ministry you are involved in; and if you heard from God to go and make disciples of men and women, and most importantly you love what you ate doing and it is producing FRUIT ... you really don't need anyone's approval, nod of acceptance, or blessing.
What you do for the Kingdom is ULTIMATELY between you and God, so stop looking for kudos from these cyber brothers and sisters. They may mean well, but they don't and can't be expected to to really and honestly know you as a person. Nor can they even start to understand the depth and breadth of what you do and why, so the best you will receive here is cyber opinions. Nothing more, nothing less. Just hand out tracks, preach to the street folks, and do it all for His glory, and your rewards will be many in heaven.
Love you for your spirit of enthusiasm to do whatever you can do to spread the Gospel in and around where He has positioned you in this world. Selah! Shalom!!!
I think we all need encouragement sometimes, and even appreciate "validation" among our peers. We do, as a Body, rely on our peers to keep us in line, do we not? And one of the beauties of Forum fellowship is most here are students of the Word, so where better to challenge our Theology and Ministries?
The OP is fairly simple, it is the question, basically...
"...is open air preaching a valid ministry?"
That he feels that people have spoken to him in discouraging, rather than edifying ways, is not something we should be surprised about either. And it cannot be denied...I have personally witnessed this, and was shocked, because we don't have many who have the courage to do what he does. It is, in my view, a gift from God and it is my opinion God is leading him in this.
We should encourage, and edify, all of our brothers and sisters in whatever ministry they perform.
God bless.