It's not about legal tender; that's just a way to exchange value. It's a brutal truth, but worth is defined by what resources people are willing to give up for something. If they are not willing to trade their resources for yours, you have NOT created real value, but destroyed it, by consuming resources that people would pay for and creating something they won't.
In the same vein, railing against profit is ridiculous; Profit is the difference between your inputs and your outputs. If you don't create a profit doing something, you are again destroying value. (It's perfectly legitimate to have a profit in non-monetary terms, though. In that case it's you who is making the decision to trade more resources for less, because the process or result has value to you; You decide on its worth, and pay the price.)
I'm not railing against profit in itself, I just find that sabotaging a good solution that would profit many people (but not you in the short term) is illogical.
In the same vein, railing against profit is ridiculous; Profit is the difference between your inputs and your outputs. If you don't create a profit doing something, you are again destroying value. (It's perfectly legitimate to have a profit in non-monetary terms, though. In that case it's you who is making the decision to trade more resources for less, because the process or result has value to you; You decide on its worth, and pay the price.)