I have a suggestion for this Twitter user if he (or she, as the case may be) feels so victimized: don't put your photos on Instagram in the first place! It's not as if they have a gun to your head and there are plenty of other sites where you can post your photos. Move on and stop complaining.
Could you imagine if everyone moved on from Instagram? A world without Instagram would be a world without blurry, scratched, sepia-toned, "artsy" pictures. Would it be such a tragedy to go back to the times of having to look at crisp, clear, 8-megapixel photos with accurate color tones again?
The Twitter user clearly thinks it's unfair to use someone else's property without paying them for it. To make things even, he should ask Instagram to, oh, I don't know -- let him use Instagram without paying for it. Oh, wait ... he already does.