You do realize that market cap is not real money, right? That's like saying that an average American who earns 30K USD/year over 33 years will earn 1M USD and thus they should be considered a millionaire.
Most of an individuals networth is likely tied up in their primary residence and highly illiquid.
If you want, you can repeat my math comparing personal income to corporate income. The difference you will find out is not substantial.
What amazes me is they are giving money with no strings attached, and of course there will be some entitled prick who will try to find fault at that. I wish more companies did "PR stunts" like these...
That said, you weren't all that far off. Based on Shopify's revenue of $4.6 billion and an average household income of $67k, this is equivalent to a donation of $14.57.
I still argue that the presence of this kind of negativity in every thread about corporate donations is toxic. Corporations don't donate to FOSS nearly as often as they should, and there's no harm in giving them some credit on the rare occasions when it happens.