Note that this preface was not allowed to be published together with the book, it was censored last minute by the publishers. The public narrative about Animal Farm is almost exclusively that it is an allegory for the USSR, an attack on the false equality that they professed. The preface explaining that it's very much intended to attack the UK and more generally European and US governments' tendencies is even today not included in the vast majority of printings of Animal Farm.
I wasn't aware of this proposed preface[0]. It's a great read and is, interestingly, somewhat applicable to the TikTok situation. However, you are incorrect, the preface does not say the book is intended as an attack on the UK, European, or US governments. What it does discuss, is how, primarily, the British intelligentsia resisted the criticism of the USSR in the book because of the wartime alliance between the UK and the USSR. The preface makes it quite clear that Animal Farm is in fact an attack on the USSR specifically.
Actually, I'm not sure if this is the preface the OP was talking about, in fact it's not clear to me who the author of it is. There's another preface[0], from the Uranian edition of Animal Farm, that they might have been referring to.
While it does contain some criticism of the the UK, quite expected as Orwell was a socialist, it also doesn't claim that Animal Farm was really about UK, European, or US governments.
EDIT: I found the primary source[1] of the unpublished preface, it does list Orwell as its author.
