Why can't I Remove 'Health' App from my iPhone SE?

First disable the Screen Time Restrictions, if any.

There are six possibilities

1. Delete an offloaded App
2. Delete an App from the Home Screen
3. Remove an App from the Home Screen - Will be placed in the App Library
4. Delete an App from the App Library
5. Delete an inbuilt App - Not feasible
6. Delete an inbuilt App with one feature - You do not get any options either (e.g. Magnifier)

Watch the GIF

HATEinstalledApps wrote:

Why is it not possible to remove/delete unwanted installed apps from my phone?

The short answer is "Because that's the way Apple decided to do things". The longer answer is this is a user-to-user technical support forum. No one here knows why Apple has made a particular design decision.

You can let Apple know your thoughts on the matter here:

Product Feedback - Apple