The house elf has been used as a slave/servant/maid/babysitter/butler/etc. and is never paid.
Most people who own a house-elf don't treat it well at all, instead, they treat as if they were garbage. House-elves have feelings, too, and they feel desperate beacuse their whole life is pure work and work without any reward. A miserable life, indeed. They're desperate, and desperate House-elves deserve to be treated with dignity. They need to be treated better, rather than just working all day long and getting beaten up whenever their work doesn't satisfy their boss/owner.
