Yes, but we all draw lines between what we do and don't give moral consideration to. For non-living things, like rocks or water molecules, we offer no direct moral consideration (ignoring potential indirect effects). Unicellular organisms merit the same lack of consideration, in my opinion, given our current scientific understanding. The scientific understanding may change in the future, but that's my current stance.

We are all one conglomerated living creature - the many twisting branches of the LUCA - but over time different aspects of this creature emerged with varying levels of complexity and information processing capability. One could argue that a lot of our atoms come from stars, so why treat ourselves any differently from stars, or that all matter and energy in the universe is just the offspring of a unified low-entropy blob at the Big Bang, so what difference does any of it make anyway.

There is some logical truth to this reasoning, but if we assume sentience to have at least some effectively non-illusory component, then I think it makes sense to consider sentient systems very differently from non-sentient or almost-non-sentient ones.