Why do you need to learn statistics for machine learning?
You need to learn statistics to be able to make sensible decisions about the ML models you plan to use, for example:


which model to use?
is the training-set large enough?
how to measure the model performance (which error measure)?
how to judge if the result is good enough?
how to (correctly!) compare different models and correct for multiple-testing?
how to avoid/identify selection bias?
how to deal with correlated features?
how to interpret the coefficients of the multiple linear regression model you just trained?


And most importantly: you need to learn statistics to understand that these questions (and many other ones) are important to ask.

If you want to be a software developer you may not need to learn statistics (although it will still be super useful!). But if you want to be a data-scientist, machine learning engineer or AI expert you cannot do your work properly without it.