Not so sure about no evidence whatsoever

I did look at this .

https://pubmed.ncbi.nlm.nih.gov/31089868/

Conclusions: Our findings are in line with most previous investigations and support the hypothesis that dairy and milk intake are associated with higher IGF-1 concentrations.

https://www.sciencedirect.com/science/article/pii/S0261561421002132

Conclusions: These results show differing associations with IGF-I concentrations depending on the source of dairy protein, with positive associations with milk and yogurt protein intake but no association with cheese protein. The positive association of fibre and starch from wholegrains with IGF-I warrants further investigation.

And this study of 40,000 humans seems to show a link between high IGF-1 and some cancers: https://www.ceu.ox.ac.uk/news/study-of-almost-400-000-confirms-that-higher-blood-levels-of-igf-1-are-a-risk-factor-for-several-types-of-cancer

"Together, these results suggest that controlling IGF-1 through lifestyle interventions could be an effective preventative measure for a range of cancers. ‘There is some initial evidence, for instance, that higher dairy intakes can raise IGF-1 concentrations"

I know some have hypothesised that this is down to bovine IGF-1 in the milk but this UK government review says that is not likely: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/803092/COC_2018_S01_IGF-1_Non-technical_summary.pdf

I also realise that milk is associated with a LOWER risk of other cancers.

But....whilst this is all quite preliminary, it certainly doesn't shut the door on the hypothesis that certain proteins, from different sources, can have specific physiological effects, including raising IGF-1, that are associated with specific risks.

I edited the initial post too, to add a link suggesting that animal proteins are more likely to cause uric acid kidney stones. Again, more evidence that these amino acid profiles can and do actually matter.