No, you're the one contradicting yourself. You shouldn't project that fallacy onto anyone else.
You're mixing metaphors.
You're taking from Matthew and meshing it with John, a book written much later and to a different audience.
So yes. If you combine thoughtless interpretative technique and abandon all common sense, you can pretend that there's a contradiction here.
But as it stands, the two sayings are completely unrelated and should be treated as such.
Isn't it common Christian belief that all of Scripture is divinely inspired and therefore congruent? If one part of scripture does not agree with another part of scripture a contradiction occurs. That's not thoughtless interpretation. That is logical proof within reason.
If you take a belief and say that the bible is divinely inspired and therefore the truth. But you have two or more things contained within that do not agree with eachother then how could it be the truth? Whether it is contained in one book of the bible or the next, all things contained within the bible are dependent upon eachother. If they do not all come into agreement then how could someone say that the bible is divinely inspired and therefore the truth?
I don't pretend there's a contradiction. Any good shepherd would know that in order to be a good shepherd you do not turn your flock over to the wolves. No contradiction there.
Jesus says, I am the good shepherd. Then he says, I send you as sheep in the midst of wolves. There is the contradiction. How does the good shepherd send his sheep to the wolves? The two things contradict eachother. A good shepherd does not send his sheep to the wolves.
The two sayings are completely related. First of all he says he is the good shepherd then he talks about sending sheep into the midst of wolves.