I don't have the profiler diagrams with me, but in general validating IRIs and literals by Jena can take up 20-40% of runtime in jelly-cli... Most of the time this is not needed, because we only want to convert one format to another.

Suggestion: disable validations by default in all commands except rdf validate. Allow enabling it with --validate-terms.

I tried doing this before, but I got stuck in Jena internals. Maybe we can override the NodeFactory somehow?