Well, you may think that if you wish, but Karl Marx says differently. In the
Communist Manifesto, Marx says the following relating to the characteristics of the "advanced" (ie socialist) state:
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.
In deciding whom to believe in describing the socialist system, you or Marx, I believe Marx.
I can understand why this would be a popular excerpt on rightist websites, but unfortunately, there are several problems.
Firstly, the term "income tax" is a mistranslation; Marx uses the term "steuer," which merely meant "tax" or "taxation," and does not specify an income tax.
Secondly, I didn't claim that progressive taxation couldn't be an element of "socialism"; I merely claimed that taxation as currently used was just as effectively a stabilizer component of capitalism, and considering the role of the diminishing rate of marginal utility (which always seems to be neglected by rightists on Internet forums; did Hazlitt not cover it?), and the complementary role of welfare in maintaining the physical efficiency of the workforce, progressive taxation functions as an especially beneficial agent of stabilization.
Thirdly, your comment about "the socialist system" indicates that you believe that the only form of socialism that exists is Marxism, which is similarly fallacious. For instance, we could consider anarchists like Mikhail Bakunin, who find their groundings in a form of libertarian socialism separate from Marxism. As he writes in his 1871 manuscript
Statism and Anarchy:
We have already expressed several times our deep aversion to the theory of Lassalle and Marx, which recommends to the workers, if not as a final ideal at least as the next immediate goal, the founding of a people’s state, which according to their interpretation will be nothing but “the proletariat elevated to the status of the governing class.”
It's also necessary to consider market socialists who oppose an ultimate establishment of any communist economic framework and prefer to retain wages and competitive enterprise, though they favor some form of collectivization of the means of production.