Although it may sound like the author is speaking to us directly as Chapter 1 begins, we don't want to assume that the author and the narrator are the same person. So, let's consider instead how the narrator of Matilda addresses parents who dote on their children, and then you can take a pretty good guess as to whether those views are also held by the author.
The narrator spends the first six paragraphs of Chapter 1 talking about how terrible it is when parents dote on (spoil) their kids. This discussion is very funny, and enjoyable yet shocking for kids and parents to read. Let's take a close look:
"Even when [doting parents'] own child is the most disgusting little blister you could ever imagine, they still think that he or she is wonderful."
This means that some parents have a kid who is a total monster, with awful behavior, and yet the parents still believe that the kid is "wonderful."
The narrator goes on to say that parents can be "blinded" by their love for their kids, and then these parents successfully lie to themselves about how smart their kids are. Having to hear these proud parents talk about their so-called brilliant kids makes the narrator want to throw up:
"'Bring us a basin! We're going to be sick!'"
This is funny, of course, but the narrator doesn't stop there. He describes how he'd like to deliver a reality check to parents like this by writing horribly insulting (yet true) things about their kids on their report cards. Here's an example of an insult he'd love to write about a stupid child whose parents believe she is smart:
"'Fiona has the same glacial beauty as an iceberg, but unlike the iceberg she has absolutely nothing below the surface.'"
In sum, the narrator addresses the subject of doting parents by exploring how annoying it is when they over-value their children and overestimate their children's intelligence, using humor and exaggeration.
But ultimately, all this discussion is just a way for the narrator to explain how terrible it is when parents don't care about their kids at all. All this humor, then, has been a lead-up to the assertion that "far worse than the doting ones" are the parents who aren't even interested in their kids.
That's when we meet Matilda, and that's when we understand the unfairness and tragedy of her parents' lack of interest in her.