Okay so I did some more research, and read the link you provided, and then read links the author of the blog pointed out, and noticed they kept talking about milk.
So I read more, and saw while most of research points to milk as being an issue, all the others except the .com link provided by the author seem to say it's just milk and not cheese or yogurt... In fact, one document says the IGF seems to be processed out during the making of other dairy products. Only one .com link included all dairy, but IMO .com links are not credible research sources. And I'll be honest, I work in research and I don't trust .com links when their references aren't clearly sited. If it's not .org/.edu/.gov, then I usually am more wary of the source.
That being said, at this link here:
Dairy foods other than milk (ice cream, yogurt, and cheese) did not have an association with IGF-I. It is possible that either IGF-I in cows’ milk or a substance in milk that stimulates endogenous production of IGF-I is inactivated during the processing of milk to ice cream, yogurt, or cheese. There was an inverse association between ice cream intake and levels of IGFBP-3. This may have to do with the saturated fat content of ice cream. However, cheese also has a high saturated fat content, and no such association was seen with cheese.
And this link that the blog posted (in her comments):
A second study found that IGF-1 levels rose in tandem with women's intake of protein, especially from milk. There was no association between IGF-1 levels and vegetable protein intake. Yogurt, cheese, and ice cream also had no association with the hormone.
Two credible sources IMO.
Good luck with whatever you decide to do! It might work for you, my one friend who has PCOS has significantly reduced her dairy intake and feels good about it
BTW even the blog author posted this in the comments (in case you don't read them):
I’ve done some more research and it seems that any milk produced by mammals has IGF-1 in it so that rules out goat’s milk as an alternative. When it comes to IGF-1 in cheese and yoghurt, it looks like it is destroyed or made ineffective with quick fermentation processes so technically, they should be okay.
The only other thing to consider is that the protein in dairy causes a huge insulin response (more than you would expect considering it’s sugar content). So, your insulin levels may still react strongly to cheese and yoghurt. I have personally decided to cut out all dairy products and I feel much better for it. You could always try is for a month and slowly reintroduce it to see how it impacts your PCOS symptoms.