n = 40, this is junk. they couldn't even get 100 people for this?
these were all sampled from 1 company in amsterdam. the differences could be explained by company culture, or local culture, or whatever. more work needed.
n=40 isn’t actually bad for generalized conclusions, given a reasonable spread in the results. Your second point is a much stronger argument. The sample is entirely non-representative.
IIRC from stats n=32 is generally considered the minimum to be considered representative for a random sample (and this is not a random sample outside of the company in Amsterdam 🙄).