It’s less that digital things can’t be alive and more that to be alive you need to exist independent of technology that’s simulating your life for you. All biological organisms pass this test. Data passes this test. The Doctor and every other hologram does not.

If you want to call the human body and perception an equivalent, I’ll point out that when you cut yourself something has actually occurred to your physical body, it isn’t just your brain seeing a knife and deciding it hurt you.

But hey, you are welcome to disagree at which point holodecks become extremely unethical. This is, after all, just philosophy.