This post is for civilians, that is, for those who might need some Hinduism 101---and that is no crime. After all, not many have a chance for formal study, even introductions. So let me make just a few very superficial comments so that some less familiar can try to understand why it is obvious that these good folks are offer their ritual to the vaccine chest.
I will be brief, if you can believe that. But as we shall see, belief is not what is being shared so much as it is behavior that allows us to ponder and conside, even for a brief moment, including our beliefs.
This is a rather typical looking puja. Puja is "worship" but that is misleading so let's instead think of puja as recognition, offering, exchange, principally _seeing_, that is an opportunity for exchanging vision, for visualizing, for deeper "seeing" (darshan).
The moment of puja captured here is it's summation called the arhati, which involves the waving of fire after offerings of incense (dhupa), light (dipa), food (naivedya), and other substances of symbolic value (hence considered auspicious or sacred). It is literally creating a moment of value---the word "arhati" _literally_ means worthy, capable, and something like noble-lizing or valuable.
People come in their temple best to honor the light inside and out. That it is directed to the vaccine chest just shows you that nearly anything of individual and social value can be brought into a collective act of value recognition, of seeing.
If any of this strikes you as awkward or just unusual, we can easily dispel the latter. This is nothing unusual because any important object or event can be occasion for puja. We have no idea what people are thinking or believing here. No one will ask. There is no dogma or formulated pre-interpretation; there is no assumption that people share a particular faith or ideology. No dogma is in evidence but rather a simple orthopraxy.
Thus, we have a ritual that lets people feel and think in ways that give them purpose to live with the facts of their world and with the shadows of feelings that are better expressed than denied. You do puja to the vaccine chest because you want light in a world where so much that is dark is dismissed or uninvestigated, particularly in emotion and meaning.
The ritual itself is meaningful because it is principally an opportunity to mark significance, to reflect or consider even in a simple ceremony how to arrive at a more auspicious (affirming) sensibility of possibilities. We invite and dispel, we recognize and address: the "gods" and the "demons" are inside _and_ out. The power of recognition is an invitation to reflection and care. Will that do for starts?
If this still strikes you as unfamiliar or awkward we can then invite the idea that unfamiliar and awkward are invitations to allowing discomfort to be a reflection. Let me go further. Is something about this idolatry or seem...dare I say, silly? For Hindus this is not at all silly precisely because it is an individual and social opportunity to see, to try to recognize significance and value _as such_ and then to put those matters into a very everyday and practical situation.
This vaccine _is_ important and it does signify light (the gods) and our complex relationship to the demons (in this case, disease). We don't eradicate our demons but we can figure out how to keep them where they belong---because everything has to go somewhere.
As for the "idolatry" part, that's just your western customs steeped in iconoclastic religions. We may not know or recognize it but our awkwardness comes from a resistance that this is "golden calf" material. But alas, it is just another human way of saying how do we see what is important in ways that inspire us to do something of commensurate value.