It says high porosity is often a result of damage and that is true. I don't see where it says all high porosity hair is unhealthy. Lots of people have healthy hair that is high porosity. The article gives good info on how to determine porosity aside from just a float or slip test.

I think normal porosity is maybe more desirable but it is not necessarily more healthy. I have low porosity and I know I'd love it if it was more normal so it would dry a bit faster!
remember, with all advice or suggestions for your hair, YMMV!!
My hair:
2b wavy, medium texture, low porosity, med-high density. Protein finicky.
My routine:
Cleansing: DCNP, every 4-5 days (occasionally use CJ cleansers).
RO: CJSC, occasionally use JCDC
Gel: KCCC, CJCIAB for 2nd day hair (sometimes third)

Heat is my friend: warm water rinses, steam caps, and diffuse dry. I love CLU cloths and my Denman.