You can’t compare US benefits to UK benefits. I’m fairly certain Atlassian’s EU offices will have very different parental leave to the US. IIRC, Aus is 6 months
Especially if you're (I'm not) pro positive-discrimination: the 'time with newborn vs. work/pay/career progression' decision is awful for gender equality, surely? Traditionally it is indeed maternity leave, and if you don't even mandate a good amount of that then the 'better hires' are men (all of us, family size decisions aside), women who won't-have/have-had children, and women who value career more.
(^: I say 'leaning' more because of US/UK political spectrum differences than anything else; feel free to read 'pretty solidly Conservative' in a UK context.)