Why were anti-federalists against ratification of the u. s. constitution?

The Antifederalists, like John Hancock, were devout revolutionaries that feared that the imposition of a more centralized government could result in an unchecked arbitrary power like that of the British monarchy of which they had just fought a revolutionary war to avoid.

from the conditions of the working class in england by friedrich engels,the main idea is :

manchester's leaders hoped to oppress its working class to benefit factory owners.