They mean that in the mind of "the general public", Tesla is the foremost company "doing stuff" about climate change. Therefore, by owning Tesla stock you can get warm glowy feels about making a difference. You might also gain coolness points by mentioning that you are "a Tesla investor" to people that care about such matters.
I may be wrong—I own no TSLA and I'm pretty much the furthest thing from a professional investor—but I didn't think the comment about being "the climate change" company was actually about warm fuzzies, I thought it was about the potential financial upside.
My understanding is that very likely—whatever green energy technologies win out—energy storage and load shifting will be a major issue.
The entities that can build energy and power storage effectively and at scale will have a new and large market opening before them.
Tesla is in a decent position—by being near the front-edge of battery production and scaling there's real room for Tesla to be a major player in the world energy market.
There’s an element of this amongst retail but I’m talking about professionals. A diversified portfolio has to have some aggressive do or die growth stocks. TSLA is (or was) probably the best of this breed. So if you’re going to own a change-the-world-or-die-trying stock, TSLA is the go to for many.
