It doesn't need to be alive to be beautiful. There is great peace and beauty in empty places. Mars has grand and majestic vistas: canyons and plains, dunes and mountains. Reducing it in your mind to a lifeless rock obscures the awe and wonder. It is the opposite of appreciation, it makes the idea small in you, worthless and not deserving of respect.
That is your perspective that it is beautiful. What if my perspective is that it is more beautiful inhabited, alive, and sustaining an ecosystem it probably hasn't for millions of years?