I have randomly known a guy who represents another example of how open source can go wrong - "you want me to fix PCI code, and on top of spending days if not weeks of work on it I should pay for the privilege of buying a PCI XIO bridge from you?" - I had contacted him with the idea of collaboration in mind, and he asked hardware donation like if you are obliged to pay someone.
That's crazy, a donation is a voluntary decision that you make if you like to do it, and it cannot be imposed by anyone for any reason!
No, you're in the wrong here, legacy.
Now,
I happen to know your intent was not to get a new "customer", but simply to invite a new person to participate in the development. Yet, that is not what it looks and feels to anyone on the other side.
You see, I've been on both sides, and I can tell you that being on the other side, treated like you treated that person,
hurts.
What you did, is akin to asking someone to come to an art exhibit, but at the door, tell them they need to pay for their own ticket. Or asking someone for a bicycle trip, and when they say they don't have a bike, you offer to sell them one. It does not work that way; you look like someone wishing to exploit others if you do that.
You need to learn to examine your interactions from the other side, to understand how your actions and communications are
perceived, because others cannot perceive your intent directly. I am telling you this, because this is exactly what I myself had had to learn to do.
If you look up
invitation in a dictionary, you can see some of the associated expectations. The associated term
solicitation should tell you there is a negative side. Consider yourself being invited for brunch, for it to turn out being about you buying something from that person.
When we talk about building a community, inviting new members with technical ability is delicate. It is very easy to be seen as looking for free labour to exploit. A lot of companies and clients do that -- either as "skill tests", or as "you'll get so much kudos for this!". So, the community organizer needs to prove their good intentions
first. I am sure all developers have found themselves in a situation they have been exploited for free or cheap labour, and most hate it as much as I do.
The way you should have approached that developer person, is to offer to lend them one, explaining that as a small community of volunteers, you cannot yet afford to buy them one.