Netflix are right that 5-stars is too many, it translates to a 6 point scale when you include non-rating, and I don't think there is a consistent view on what "3 stars" means, and how it's different to either 4 stars or 2 stars ( depending on the person ).

For some people 3 stars is an acceptable rating, closer to 4 stars than 2 stars. For others, 3 stars is a bad rating, closer to 2 stars than 5 stars. And for others still, it doesn't give signal beyond what a non-rating would be, it's "I don't have a strong opinion about this".

Effectively chopping out the 3-star rating, leaves it with a better a scale of:

   - Excellent, I want to put effort into seeking out similar content
   - Fine, I'd be happy to watch more like it
   - Bad, I didn't enjoy this
   - Terrible, I want to put effort into avoiding this

With the implicit:

    - I have no opinion on this

But since it's not a survey, it doesn't need to be explicit, that's coded into not rating it instead.

These are comparable to a 5 point Likert scale:

    "I enjoy this content"

   - Strongly agree
   - Agree
   - Neither Agree nor Disagree
   - Disagree
   - Strongly Disagree

The current Netflix scale effectively merges Disagree and Strongly Disagree, and for matters of taste that may well be fine.

It would be interesting to conduct social science with a similar scale with merged Disagree and Strongly disagree to see if that gave it any better consistency.