I could give nothing to charity, and that would have no impact on my argument whatsoever.
Number one, I don't agree with your argument. Lives can be saved by donating to Erowid, the EFF fights for liberty - which is a very important thing for those who aren't dying, and there are many other good charities that aren't directly responsible for saving lives. It does no good to save all the orphans in Africa if the rest of the world turns into a police state because nobody was trying to protect our freedom.
Number two, if you don't give to charity but try to make others feel like shit for giving, that makes you an ass.
I'm glad that you give, but the fact that you're kind to others doesn't grant you the right to be an ass to other people. You literally said that giving to Erowid and not giving to other charities is "at the expense of other peoples lives", which pretty much means they're indirectly responsible for those deaths. No other way to interpret that. They didn't donate, the dying people didn't have enough money to be saved, so they died. It's an offensive statement. Not every individual in the world can be responsible for saving the life of every other individual in the world.
If you want to blame somebody for deaths in this world... well, I see you live in the UK, so I'm not familiar with your shitty politicians over there. But you can still blame many other governments. The US has many policies responsible for peoples deaths. Our police and prison systems are corrupt and thousands needlessly die every year to violent police action or violence and neglect in prisons. Thousands more die due to America being involved in unnessecary wars.
If you want to blame somebody for doing things "at the expense of people's lives" (direct quote from you), I would start at the top. I'm a fairly wealthy guy and I donate a lot, but it doesn't make a dent in the number of lives that can be saved if the people at the top had the same level of compassion. Imagine a world without wars. Imagine a world where governments didn't try to oppress their own people. We'd be so free then that we could do so much more good in the world.
Nobody should ever be shamed for helping others. That's the bottom line.