You are interpreting the First Amendment without any clue as to why it was enacted and how courts interpret it. Language only gets you so far. You need to know the history behind its enactment. Basically, Americans were British subjects traumatized by the religious wars in Europe that waged forever. As English subjects, they knew the bloodbath of the estabishment of the English Church and even the battles towards the Catholic spectrum of the Church of England vs. the Puritan spectrum. King Charles I was beheaded. England had no formal king for a period. A dictator ruled.
The problem was compounded by the fact that America was largely settled by dissidents from the Church of England. They did not seek freedom from religion as much as imposition of their own brand of religion as the legal, permissible one. English Presbyterians could not marry English B aptists. Religion influenced everything. Politcal power was exercised through religion. Unable to impose their particular view, a consensus grew not to establish any religion. You may want to read James Madison's writings or the wikipedia article.
In terms of petitions, I worked in the Senate. Petitions don't carry much clout. Personal letters tend to do so. It does not make much energy to sign a petition. Personal letters work much better. All petitions prove is the marketing behind the petition. My office tended to just throw them in the trash can.
You have no legitimacy to impose your view of dangerous on the American public. If they are dangerous, they probably engage in criminal activities. Criminal laws imposed on everyone with no legislative history of an attempt to persecute a particular religion have always been upheld. So the criminal law stands as a barrier to dangerousness. Dangerousness of content is protected absolutely the federal const'n. As I wrote, this is my area of expertise. Conservative and progressive justices agree completely with what I wrote.
One of the main reasons tax exemption is allowed for religions is that government had a radically different mission in American life at the founding. Government, particularly the federal govt, was very limited. Changes in technology, economics, public values have transformed American life. The New Deal was the prime mover of this trend. In colonial times, charity and taking care of those who cannot care for themselves was viewed as a Christian duty. Only churches provided orphanages and hospitals. Americans need some social safety net. The Founders would be shocked by govt. funded orphanes and hospitals. With the government entering the field, however, there is much less rationale for religious tax exemption.
Also, the Founders did not define Establishment in the First Amendment. It was a matter of controversay. The Const'n defines our values. It can't be detailed as legislation. When in doubt or unable to reach a consensus, vagueness allows both sides to claim a win. We view the Establishment Clause as so essential today. When it was enacted, not much comment or legal debate ensued. The first legal case under the Establishment Clause did not come before the Supreme Court until around the Civil War. One hundred years with no litigation makes one wonder.
Today's cases are a motley crue. They are controversial. The Court is split with no clear direction so that people can conform their lives to the law. What is agreed is that we will not have any Church of England religion in America. Unfortunately, the Court has never been as clear as the language of the Clause.