The bar for legal US immigration is low and it is intentionally made easy to immigrate. That is why some people don't think we should be giving a free pass to the illegals. They essentially bypassed taking a couple days to learn the Constitution and a basic English test and an oath of loyalty to the US.
Interesting statement. It clearly indicates you know nothing about immigration to the US. While it is (relatively) easy to get a student visa to go to school in the US, it is far more difficult to get a resident-work visa. To get a resident-work visa, you first need to find an employer who is willling to sponsor you, fill out the paperwork, and pay the fee. Then you need a labor certification from the Department of Labor, more money and time. Then you can file the actual visa application (money) and wait for an eligible date (time). How long this takes depends on your visa category and the country you are applying from. If you are in the E3 category (Skilled Workers, Professionals, and Unskilled Workers (Other Workers)) and applying from an oversubscribed country (ex: Mexico), this can take a long time. Only 140,000 employment-based visas are granted for 2012. With a 7% cap on each country and an ~29% issuance to the E3 category, a restaurant worker from Mexico would be competing for one of ~2800 visas granted this year. They likely won't get it and will have to wait until the following year or longer.
That is the minimum required for immigration to work unless you are in the priority category or have some other kind of exemption. You could stop there. However, your visa will expire eventually and usually cannot be renewed. So if you want to stay in the US, you have to start applying for permanent residence, which is another big hassel that takes a lot of time and money. Without at least a Master's degree (PhD is better), you can be waiting for a lottery number for a very long time, and paying a lot of money in lawyer's and application fees.
So, no, it is not easy to immigrate to the US. It is arguably easy to figure out what forms to fill out and submit them, but it is not easy to get the actual visa that you need to get, which then allows you to get the permanent residence, which then allows you to apply for citizenship.