Viruses absolutely do respond to their environment and stuff in spectacular ways, understanding of viruses has come a long way since we thought they were dumb little protein shells
Sorry can you back this statement up? Cursory searching says this is not the case.
The only reference to 'responding to environment' is when that environment is inside of a host/cell. The rest of the time it's inert. When placed in a literal empty box, it is a dumb protein shell.
Took a full virology class, not sure what exactly to source. I went back to the lecture notes and pulled a few examples. They ride cell cytoskeletons, respond to PH changes to escape vescicles during infection (and it's awefully hard to draw the line at "this is just a chemical reponse" when it comes to biology, especially because if proteins doing their thing doesn't count as responding in a lifelike way, then nothing's alive). And also, yes exactly, viruses respond inside of the environment of a host or cell. That is their environment. Obviously you wouldn't expect to see any response to environment if you put them in a box with no environment - we would also be very dead in that case.
Role of receptors - interactions between viral receptor proteins and their hosts are incredibly complex, and include the virus signalling to the host to be more conducive to infection
And of course one of the most fascinating parts of virology (in my opinion) is viral surfing and active dissemination (active meaning they do things to infect cells instead of just floating around and bumping things). Viruses bind to a host and then actively move until they reach an ideal entry area
And there are many more but hopefully those are some helpful keywords. But I think you can get a sense of why many virologists treat viruses as living - they are dynamic and interact with their environment, and they evolve under the laws of natural selection. And the more we understand them, the more we realize preconceived notions about them (we originally thought they were just a poison, then some biological chemical, and then dumb protein shells, and now see that they can actually do a lot of crazy stuff - which makes sense because how would a dumb protein she'll be able to stay evolutionarily fit for millions of years against our immune system?