I've been registered at the White House petition site for a year and have not been receiving emails other than a notification that my petition is up and running. I may have received an email when I first registered; perhaps I unsubscribed from receiving other types of messages.
You may be right that TMC members feel frustrated by the lack of a response to the Tesla petition involving dealership laws. The issue is politically charged. I wouldn't deem an alternate reason to be "pretty clear". Since the FTC has responded positively, I wouldn't be surprised if we soon get a White House response. Right now their attention is towards the Ukraine.
Many people will feel that their one signature will make no difference. Collectively that attitude puts a damper on things. Not only should they sign, but they should encourage others through social media. Today I tweeted Elon Musk and SpaceX to notify them of the petition. The earlier Tesla petition did not get rolling until Elon tweeted about it.
