Sadly this has become practice among some other online stores as well. I heard some Amazon sellers contact people who make bad reviews. They even go as far as to bribe them to get the review removed. Would be interesting to hear how much Malmquist is ready to pay.
Anyway, what this clearly shows is that those reviews matter and affect the sales, which is a good thing.
An Amazon seller tried to bribe me. I told Amazon and they refunded the full price of the item AND my review stayed put.
"BPS proponents dont respond well to criticism"
And the prize for the biggest understatement in a thread title goes to....

I'm with
@Kittyi'm sure people would find it hilarious. Can you imagine a respected author doing that? Lee Childs perhaps, or Alexander McCall Smith? LOL
It sounds like it's kept him up nights if he's sent several emails. He should try being awake all night with symptoms of ME that might change his perspective a bit
Most authors don't engage with bad reviews for their own wellbeing. But some go absolutely ape-shit.
Kate Clanchy, a Scottish poet, wrote this book about the children she worked with at schools, referring to their body traits with such odiously colourful language as a 'Cypriot bosom' and 'Ashkenazi nose' (bear in mind these are kids!).
There was also some awfully ableist stuff about autistic kids and how she couldn't suffer to be around them for too long, how poor they were at socialising, and how she'd trick them with mindless, endless tasks so she didn't have to deal with them.
A reviewer pointed all this out in GoodReads, some two years after the book came out, so she went ballistic, called the reviewer a liar, implied that anyone who had read the book and thought the same was a liar, and watched as three women (well known writers who confirmed the reviewer was accurate) got death threats and racist abuse on Twitter.
Then Philip Pullman waded in--with half the facts and without having read the book at all, mind--and said anyone who judged a book without reading it was akin to the Taliban or ISIS.
Only, the three women getting all the abuse were two South Asian women and a Turkish woman, so it didn't go down well to imply they were Islamist terrorists, as he had done.
Eventually, Clanchy gave a vague apology to 'anyone she'd hurt' (but not to the three women who were harassed, who she carefully avoiding mentioning at all) and Pullman said he'd mistaken a post about something else as being about Clanchy's book and responded too quickly (the irony!).
So two well regarded authors tainted their brands in a matter of days, all over a bad review--which was true! One of whom I'd expected rather a lot more from, but who was obviously more concerned about sticking up for a mate than checking his facts.