To travel around when you know you have coronavirus is the most selfish act imaginable. He chose to expose others to it. His choices may have killed people and, knowing this, he did it anyway.

If you want to use the 'visiting your lover' comparison, the moral difference between Cummings and Ferguson is the difference between someone who chooses to have unprotected sex knowing they have AIDS and someone who chooses to have unprotected sex not knowing they have AIDS.