Clearly you have not actually READ the manifesto,or much of Marx's rhetoric. Marx does indeed rail against freeloading, and outright says that any system that permits it cannot be sustained, as the number of freeloaders will rapidly outpace the number of producers, bankrupting the system. (in general in his rhetoric)
In fact, he sets the univeral requirement of *ALL* to labor, as bulleted item #8 in his manifesto.
These measures will of course be different in different countries.
Nevertheless in the most advanced countries, the following will be pretty generally applicable.
1. Abolition of property in land and application of all rents of land to public purposes.
2. A heavy progressive or graduated income tax.
3. Abolition of all right of inheritance.
4. Confiscation of the property of all emigrants and rebels.
5. Centralisation of credit in the hands of the State, by means of a national bank with State capital and an exclusive monopoly.
6. Centralisation of the means of communication and transport in the hands of the State.
7. Extension of factories and instruments of production owned by the State; the bringing into cultivation of waste-lands, and the improvement of the soil generally in accordance with a common plan.
8. Equal liability of all to labour. Establishment of industrial armies, especially for agriculture.
9. Combination of agriculture with manufacturing industries; gradual abolition of the distinction between town and country, by a more equable distribution of the population over the country.
10. Free education for all children in public schools. Abolition of children's factory labour in its present form. Combination of education with industrial production, &c., &c.
(Found in chapter 2 of the manifesto, in case you wondered)
Marx is not strictly against the providence of support for those that are physically unable to labor anymore, he just stresses the insistence that these cases need to be strictly evaluated, and limited in number, otherwise they will overtake production, and the system will collapse. For those that are able to lablor-- even just a little-- Marx asserts that it is their duty to perform such labor. This means that the paraplegic in the wheelchair goes to work doing something with his hands that does not require the use of his legs, and in return, gets the fruits of the redistribution of wealth, same as a person who has legs-- etc. Marxist rhetoric is very much against "Full disability" type welfare, except where it quite literally is true that the person cannot work at all.