I'm not exactly sure what your question is but in the US schools have the right to block any websites that they choose to block.
No but your mom should :)
They block websites that would not be beneficial to their educational curriculum.
Schools block proxy websites because they do not want students to go on uneducational websites
Because they want us to visit their website more often so their ads are viewed by us.
Information about US government grants can be found on numerous websites including the national website for Fannie Mae.
You can't. It's blocked for a reason. Workplaces block particular websites to prevent employees wasting valuable company time. Schools and colleges block sites to prevent students being distracted from their learning. Internet security services sometimes block malicious websites known to infect computers with viruses, trojans, keyloggers and so on. Governments also block illegal websites. If the site is illegal and has been blocked, your government may be able to trace you trying to connect to it. Websites are blocked for a reason.
Schools are allowed to block any websites they deem not needed in education. Since this is a secular government and the role of religion in schools is not part of education they would be allowed to block the site. This would especially true that they blocked all sites and just not particular sites. Otherwise that would be discrimination.
they should never even let their kid have one
Many different websites can be blocked. Often employers will block all websites that are not pertinent to the employees job. Parents often block websites that contain pornography and violence.
They can't control the global internet, no, because nobody legally owns the internet. The internet is the property of the people of Earth, not one single government. However, the government can control what websites are accessible in their country. For example, the British government can block Mexican drug websites from being accessible in British territories, because they are against the law.
you can download software