I think this is likely the cause of most of the consternation. Mainly because the KS campaign (does Steam EA offer a target release date? Haven't checked) did not say 'Pledge funds and please wait patiently and stick with us until it's done,' it basically said (and is how people - naively or not - understand it when contributing) 'X funds required for Sui Generis, release date Y.' Think about how annoyed people get when they order something for next week and there's a couple of week delay...The only thing I could reiterate, which has been said time and time again, is patience.
The second part is that nothing much changes. The argument settles down, it goes quiet for a while until someone once again loses patience and away we go again... Maybe that's a hint that something in the communication approach should change... As Sui Generis likely won't be released a couple of months after the next big upcoming update, if communication remains as is you'll only see a trend upward in 'toxicity,' not down.