Alcoholics are often charming people. We fall in love with the best parts of their beings. It is understandable that we fall in love.
Active alcoholics are slowly committing suicide. If we choose to love them, we are choosing a path which - even without abuse or conflict (because there are some gentle alcoholics out there) - end-story with the trauma of loss.
I loved an alcoholic who was a long distance relationship for 2.5 years. He had a secret life which - I don't think - involved other women. I think he actually loved me back. But he "made it through" our shared time sober or sort of sober, & drank compulsively when we were not together. Your point about the communication is apt - my experience is that he was always absent in communications when we were apart, because he was sitting in his special chair, drinking himself into oblivion. It hurt, & I was far away & worried & hurt. Constantly.
He had periods of sobriety, but never embraced a recovery lifestyle. He drank himself into many medical crisis which were terrifying - & hurt.
Ending the relationship was difficult. I loved him, & the loss of him hurt.
But here's the thing. He was already lost to me. He was lost to himself. And the only realistic future was his loss - through some version of an alcoholic death.
He didn't contain the capacity for partnership. He just couldn't give me what I wanted - which was someone who might be there for me.
Just because we love someone doesn't mean they are destined to be our partner. And that's ok...