It does seem a counter productive measure. I am an example - I earned 100k just before I had children, over a decade ago. I am not expecting sympathy, but I have made what I thought were rational decisions due to policies like this and the result is:
I took longer mat leaves than planned, bringing my income down for that year
Large pension contributions
Have only worked 4 days/week since
Buy extra holiday/take unpaid
Bought a smaller house than planned, as I moved when children were small (not an unusual time to move id have thought?) and my nursery bill at the time was 3k/mth lowering the mortgage I could comfortably get.
The house part I think is important as , definitely for me anyway, part of the lure of the high earning life was the lifestyle - when I couldn't get what I'd envisioned it made the whole thing seem less worth it.
Anyway now ultimately I am in my mid 40s and plan to retire at 50, helped by my hefty pension contributions.
So rather than the high flying life my 20-something self saw, going for the top jobs and working into my 60s earning a high level full time wage and being taxed on same - I will spend 2 decades working at 50i-60ish% of my total possible wage (which was lower anyway due to not pushing career), and my total lifetime tax will be substantially lower