Nope. American milk is pasteurized to a much higher temp. It lasts way longer. Irish goes off in days, US milk will last a month in the fridge.
The extra pasteurization effects the taste and flavor.
High-Temperature, Short-Time (HSTS) Pasteurization appears to be the standard in both Ireland [1] and the US [2] -- 71.7°C / 161°F for 15 seconds.
And I can tell you from personal experience that US milk goes bad in days as well, and has for decades. I don't know where you're getting the idea that it lasts a month in the fridge.
There are real differences in some foods between the US and Europe, e.g. American eggs are washed while European ones aren't. But fresh milk from the supermarket appears to be very much identical.
[1] https://ndc.ie/accordion/what-is-pasteurisation/
[2] https://www.usdairy.com/news-articles/why-is-milk-pasteurize...
I did find that US allows the use of hormones to increase milk production. Possibly that's a factor? But very difficult to tell.
I really don't know why the original poster claimed otherwise. Maybe it's just an urban legend in parts of Europe or something.