Likely because their workers likely use HN, and their HR sent out an email.
It's yet another company tactic.
Like steam pages being owned by the game publishers and so banning users for anything negative.
Or like movie producers having everyone who worked on the movie in any capacity rate it 10/10 on IMDB and some write 10/10 reviews that 'saw the movie at [obscure festival]', has full names of everyone involved '[ditector] was amazing and deserves all awards as does [actor 1]. [actor 2] was oscar worthy [1st-time actor] gave the performance of a lifetime! [gaffer] also worked on [obscure film].'
Three days after release it's now at 4/10 and only because of the high starting point of 10/10.
