The blank media tax is probably a compensation (i.e. not a tax) for the right to do private copies of legally acquired media. At least, this is what it is in France.
At least in Belgium, that right has existed for ages without the compensation on blank media (cassettes, VHS tapes, ...). When they introduced the tax it was quite explicitly stated that it was a compensation for illegal copying.
Why I, who never use my CD/DVDs for copying anything but homemade content, have to pay for someone else's illegal copying is not clear to me. Especially since the tax doesn't change anything for the person who is making the copy - it's still illegal.
