Rude indeed. You may think his gifts are tat, but what about the time and effort he put into choosing and buying something? I say this as someone whose own mother gave her grandson his first present 20 months after he was born. She is the most tight- fisted woman on the planet and I felt it that she couldn't be bothered to spend even 1 pound on him (despite a wardrobe full of chanel handbags and shoes). Appreciate your fil's gesture instead of behaving like a brat yourself.
As far as I am aware they do need to know the names of the letters and the pure sounds they make which is basically the old way of making the sound but without the unhelpful schwa noise on the end. Is that right? And anyway it doesn't matter now as dc won't be paying much attention will she?
You were being pfb about it. But everyone has moments like that. I am making sure I remember as many as possible of mine so that I don't get cross with the dc if and when they have their own pfb with moments to match.
If you rejected the present on the basis that it would be unhelpful for your (4 month old) DD in learning to read, then yes, very PFB and YABU.
If you rejected the present actually because it was a horrible bit of plastic tat (and somehow you thought that it would be a more acceptable reason for rejecting it to talk about the impact on DD's reading), then YA also BU because the correct answer to being given a present, not matter how vile, is always always "thank you very much, how kind of you, what a nice thought". Then "lose" it and give to the nearest charity shop.
But a tiny bit of credit to starting a thread in which you clearly already realise you were probably being unreasonable! And you are no doubt rather sleep deprived and hormonal.