Put aside whether this was justified or not, or the potential Streisand effect or PR damage (or vice versa). What signal is this sending to the young Google engineer who wants to build the next Gmail? Even if this violated every internal policy, firing someone who created something that people actually want is sending a very disturbing message (internally and externally).
Also, is this somehow relate to Addy Osmani’s recent departure from Google? (Was it in sympathy, was it a retaliation as this was “the tweet that got OP fired”?)