>People shouldn't need a thank you email
I think it's entirely unsurprising that people would like a thank you email. If you donate to an open source project, you have gone out of your way to acknowledge the project's maintainer. The least they can do is acknowledge you back - it's basic reciprocity.
>the cost of configuring a bot to send thank you emails is so low
Honestly, I think a bot saying "thank you" is as soulless as no "thank you" at all. It doesn't take long to type up a manual response and genuinely express your gratefulness.
