"The boy does not like seeing soldiers."
Translation:A fiú nem szeret katonákat látni.
I'm not sure what you mean by negation and acc being right after it.
Anyways, with verbs that can take an infinitive, like szeret, the nuances of the word order skyrocket, as now we have two verbs. And really, this sentence is by no means "wrong", I wouldn't call it "wrong" at all. It just changes your intonation opportunities, that's all. In this sentence, you quickly set the topic to the people involved (both the subject and soldiers as the object) and then you make the statement about them. As "katonákat" is right in front of the predicate with "nem", you can stress it a bit, saying that he doesn't like seeing soldiers but for some other things/people, the situation would differ.