Firstly, shouldn’t hard and unpleasant labor pay more? Our society, and the economy, need to get over the self importance of deciding who is worthy of basic necessities to keep body and soul together. This would be critical for a basic income to work, but the benefit would be higher income potential for those who make the effort to rise above the minimum. Do you really want to be the one who goes on record advocating sub human conditions for someone who works hard because they do unpleasant work?
Secondly, even those who do nothing but spend their basic income benefit society. Spending is how markets are created and sustained. Our current miserable economic conditions for fully half of the population is not due to anyone’s laziness, but to the lack of capital available to them. Sequestered capital (bank accounts and financial instruments) is the same as no capital to the Main St economy, and our current model does nothing to free up capital. In fact, it punishes investment with higher risk that would supply capital to the lower levels.