I can program my microwave to automatically heat my soup for 85 seconds at 80% power beginning at 2pm. End users would struggle to program their smartphones to navigate HN automatically at that time.
Traditionally, programmability has been the consideration when determining what constitutes a general computing device. Browsing the web or reading email are not.
What deserves analysis are the premises upon which the conclusion about Linux has been reached. The basis upon which the conclusion about Linux has been reached relies on a special definition. When an argument relies on changing the meaning of words, its honesty is suspect.