Considering ~3% of Americans are NetFlix subscribers that means only ~900 people per Basic Zip might be subscribers. Gender will half this to ~450 people, and considering that (IIRC) each 5-year population group has on average ~5.8% of the population in it with a median age of ~38 (where the percentages are hitting 7.8%), but let's say an average 1.2% of the population is of any individual year of age.

This means, on average, you should still be able to place someone down to ~5 people. God forbid you're a 110 year old using netflix. If netflix is releasing it in 5-year groupings that still puts you in a group of ~30 people for grouping of ~30,000.

I'm unsure if any data release like this counts as anonymous.

I don't think Netflix is going to release their customer list the first reduction is not directly possible. Also splitting the population into equivalent size groupings is a normal approach, so you might start with 18-21,21-26... and end with 85+.

Also, it's normal to add / remove ~1% of your sample to remove some edge cases and muddle the waters.