Think about a startup who does not care their customers. This is Evernote (discussion.evernote.com)

Evernote might or might not care about their customers.

But that's not because they don't put out a Linux client.

A company cares about their existing customers and target market. If they don't intend to compete in Linux, then Linux users are not their customers.

And of course a company doesn't have to comply with anything some customers might want to care for their customers.