If a person that has been Naturalized in America can lose their Naturalization by being affiliated with the Communist Party, why are other communists in America allowed to flourish?

A person is subject to revocation of naturalization if the person becomes a member of, or affiliated with, the Communist party, other totalitarian party, or terrorist organization within five years of his or her naturalization.

In general, a person who is involved with such organizations cannot establish the naturalization requirements of having an attachment to the Constitution and of being well-disposed to the good order and happiness of the United States.

U.S. Citizenship and Immigration Services

https://www.uscis.gov/policy-manual/volume-12-part-l-chapter-2

The Congress finds and declares that the Communist Party of the United States, although purportedly a political party, is in fact an instrumentality of a conspiracy to overthrow the Government of the United States.

https://uscode.house.gov/view.xhtml?path=/prelim@title50/chapter23/subchapter4&edition=prelim

Public Law 637 CHAPTER 886

AN A C T August 24, 1954

To outlaw the Communist Party, to prohibit members of Communist organizations from serving in certain representative capacities, and for other purposes.

https://www.govinfo.gov/content/pkg/STATUTE-68/pdf/STATUTE-68-Pg775.pdf

Time to take this back to court?

In 1973, a federal district court in Arizona decided that most of the act was unconstitutional, and Arizona could not keep the party off the ballot in the general election

https://www.plainsite.org/dockets/1zey0ee5l/arizona-district-court/blawis-v-bolin/

https://en.wikipedia.org/wiki/Communist_Control_Act_of_1954