Here's why:
* Origin: The phrase likely originated in the 19th century and was used to describe the passionate and sometimes fiery nature of Irish people. It was often used in a humorous or lighthearted way.
* Modern Usage: While the phrase is still used today, it can be seen as a stereotype and a generalization about Irish people. It can also imply that Irish people are prone to anger or aggression, which is not accurate or fair.
* Alternatives: There are other ways to describe someone who is feeling energetic or excited without resorting to stereotypes. For example, you could say "to get pumped up," "to get fired up," or "to get excited."
In conclusion: While "to get your Irish up" might not be intended as offensive, it's important to be aware of the potential for it to be seen as derogatory. Using alternative phrases can help avoid perpetuating harmful stereotypes.