What you just said introduces a bit of a conflict with your claim that strategy is important. Sometimes you need to take calculated risks (i.e. always be reasonable, don't lose all of your assets, don't get addicted) and 'lose' money to learn how to make more money.
I think it is very noble of you to weigh your needs against the needs of others. Charity and how you should exercise it is a very interesting subject, and there are many many ways to do it optimally. See Givewell, Watsi, Mindsmatter etc. Since you are reading this, I assume you are doing reasonably well in life, so, and this is my personal view btw, you do need to give something back to those in need. However, don't let that prevent you from investing in your own education - it will very likely enable you to do more.
Yep, let me clarify, it is never OK to loose money due stupidity, not knowing what you are doing, praying the market will turn around, etc.
If you have a proper risk management and investing strategy, yes, you will have many periods and trades where you are going to loose money short term, but you'll be confident that you'll make the money back + more, because you did back test everything and you have the proof your strategy works...
I think it is very noble of you to weigh your needs against the needs of others. Charity and how you should exercise it is a very interesting subject, and there are many many ways to do it optimally. See Givewell, Watsi, Mindsmatter etc. Since you are reading this, I assume you are doing reasonably well in life, so, and this is my personal view btw, you do need to give something back to those in need. However, don't let that prevent you from investing in your own education - it will very likely enable you to do more.