If you know anything about biology, you would know that your "gray area" is something that you came up based on an assumption. Viruses are non-living.
Why?
.They don't carry out cellular respiration
.They have no proper cell organelles
.Cannot reproduce independently
.Do not respond to stimuli
They go against the criteria for something to be considered living.
Ahem, please don't insult my intelligence, I know what a virus is, and I know the requirements to be classified as life. If you knew something about biology you would know that I'm not the only person to believe that they exist in-between living and nonliving, nor am I the most experienced in biology. The theory that they exist in a grey area is not based on an assumption, but years of research by experienced biologists.
Reproduce
Obtain and use energy
Grow, develop, and die
Respond to the environment
These are a few of the requirements of life, now lets see how viruses fit into these.
Viruses are capable of reproducing, individually? no, they need a host cell to inject their genetic material and cause the cell to manufacture virus parts, the parts are then assembled and replicated until the cell can on longer contain them and ruptures.
Obtain and use energy, a virus itself doesn't need food or energy because it is not a cell, instead it provides that energy to the host cell in order to keep that cell capable of reproducing copies of itself.
Grow, develop, and die, when a virus injects its DNA into the host cell, the hosts functions are taken over and begin to replicate that DNA, and the other pieces that ultimately make up the whole virus, and while they do nothing inside of their protein shell, many scientists argue that viruses do their growing inside of the cell.
React to the environment, you are wrong here as well, viruses do react to the environment. Viruses are constantly evolving so that they can better increase their chances of survival (The need for survival also travels back to the last point, proving that viruses do indeed die) and adapt to the environment. This is why it's so hard to "Cure" a virus, because it is constantly changing it's genetic make-up. Like bacteria, they evolve through genetic mutations due to rapid reproduction (There's another one).
If you want to argue with years of research then be my guest.