If you release a product then at the minimum it's your responsibility to make sure it's not going to harm others. If you can't do this then you shouldn't be releasing open source software.
Adding a disclaimer at the bottom doesn't absolve you of gross negligence.
Because they obviously would be not legally binding. Again, you can't absolve yourself of gross negligence any more than you can sell yourself into slavery. And legally speaking, selling something almost always includes giving that thing away for free. (Except for in a few cases where gifts are specifically exempted, like for some low-level drug crimes at the state level.)