I have watched Prince many times in the past and I have never heard that statement before about "not taking doctrine from the gospels". There is the rightly dividing of scriptures too in relation to who is being spoken too. If Jesus was talking to a Pharisee - Jesus would say "you whitewashed tomb" but He never spoke that to His disciples so to try to "apply" that to believers in Christ would be not proper doctrine.
I don't agree with everything any preacher says including Prince but he is right on with the gospel of the grace of Christ. I don't even expect to agree with myself 5 years from now on everything I believe now. I'm constantly repenting as I learn new truths about the Lord Jesus Christ and His great salvation.
What many of these self-proclaimed heretic hunter websites are saying is "their interpretation" of what is being said - when you go back to the horse's mouth we find something totally different.
There are lot's of self-proclaimed heretic hunters on the internet. To them everyone is a heretic.
There are websites dedicated to the heretic Billy Graham. Billy Sunday, Charles Spurgeon, Charles Stanley, D.L. Moody, C.S. Lewis, John McArthur, Paul Washer, Joseph Prince, Bill Johnson, Martin Luther, John Calvin..etc..basically anyone who is known has a website dedicated to their "heresies"
There are even websites dedicated to the heretic apostle Paul because his epistles "conflict" with some of Jesus' words.
Basically these self-proclaimed heretic hunters have a beef about some thing with what someone else believes and so they are now "heretics". "If people don't believe the way that they do - they are heretics and they try to prove it with "their" version of what the scriptures say.."
It's the nature of the beast.
Where these types cross the line is when they turn a disagreement that they have with someone doctrinally on a secondary issue and turn it into "So and so is a heretic/satanist/controlled by a demon" type stuff.