There's no contradiction, but Kaku is being pretty cavalier.
In both classical and quantum physics, an uncharged point particle can never emit or absorb any light. Nothing about this violates the uncertainty principle. The electromagnetic field is just one of many quantum fields in the universe, and there's no law saying you have to interact with it.
Kaku is talking about something different: black holes, which classically can absorb light but never emit it. This is very different from an uncharged particle, which doesn't interact with light at all. It's true that in the quantum theory, black holes can emit light by Hawking radiation.
However, this is only tenuously related to the uncertainty principle. I assume the relation Kaku had in mind was something like "the uncertainty principle means that particles can spontaneously pop out of thin air. A quantum black hole can radiate because a particle can spontaneously appear right outside its event horizon and leave." This is the standard popsci explanation, but it's rather misleading, in the sense that nothing about Hawking's actual calculation looks anything like this.
Again, Hawking radiation is a statement about event horizons. It has no strict relation with dark matter. Furthermore, dark matter doesn't even have to be perfectly dark. For example, there are theories of millicharged DM where dark matter does have a tiny charge and hence can radiate. Dark matter could also be due to primordial black holes, which do radiate by Hawking radiation. In both cases the radiation is too little to see.