I like his videos and most of this particular video. For example, I agree with his choice to not discuss the nasty details of the FFT. Also, I think the "blur" part is fine, but the "unblur" part is too oversimplified.

I think he could have explained how the Gaussian filter almost kills all details / high frequency features, then rounding completely destroy them and then they can not be magically reconstructed to "unblur". He gives some hints about this, but they are to few and too general.

PS: There are some non lineal ticks "enhance" the "unblur" version , like minimizing the L1 norm of the gradient (or something like that). It helps with some images. I'm not sure which is the current state of the art.