With Greta as the face of the movement, consuming Greta replaces meaningful action.
In canonizing Greta, she becomes a consumable product of which consumerism is a substitute for meaningful action.
We live in a society that has conditioned us to consume at every opportunity. We buy into brands, ideas, political parties, hobbies, and causes. The younger generations, raised on the nourishment of social media, is particularly sensitive to this. Their digital life is a careful cultivation of their personal brand, which means consuming the right causes, signalling the right virtues, and buying into the right ideas. In canonizing Greta Thunberg as the face of the climate change movement, we make her a consumable object. Instead of changing their eating habits, supporters can simply retweet Greta speeches. Rather than cutting down on air travel themselves, they can share a video of Greta crossing the Atlantic in a solar-powered yacht. This consumerism of Greta often substitutes for meaningful action. But sharing a tweet and consuming Greta is not going to save the planet. 
To assert that young people are consuming Greta rather than engaging in meaningful action just isn’t true. In her most recent Friday school strike, school children from more than 130 countries left their classrooms and turned out in the streets to protest government inaction on climate change.  In New York alone, where Thunberg led the demonstration at Foley Square, there were more than 1.1 million students in attendance. These students are not consuming Greta in a superficial way, they are participating in a global social movement. Young people aren’t consuming Greta; they’re following her. To suggest otherwise is misguided and an inaccurate reading of the situation.
[P1] Part of the canonization of Greta Thunberg means she becomes a consumable product. [P2] Instead of engaging in meaningful climate activism, young people can simple consume Greta. [P3] This makes her an unnecessary distraction from meaningful activism.
[Rejecting P2] But that is not what young people are doing. They are mobilising in a meaningful way.