People have different views as to whether scientists should be allowed to send signals into space to contact with aliens or this is too dangerous. Both schools of thoughts could be true in their own rights but I agree with the latter opinion.
On the one hand, communication with extraterrestrial life forms could benefit humanity in many ways. In best case scenario, when we are able to reach civilizations beyond our technological advancement, we can accelerate our development with the help of their knowledge and understanding of the universe. It is because if there are species out in the universe, there is no doubt that they could have already developed to the point where they have reached the speed of light and start traveling across the milky way. In worst case scenario, if we are able to detect aliens on other planets which are in their simplest forms without any sign of intelligence, we can at least have optimistic view about the future of humanity. This because one day we can reach these planets to colonize them and become interstellar species. Therefore, people support scientists who are trying to reach other civilizations in space.
On the other hand, it might seem absurd for some people to imagine friendly aliens. That is to say the history needs to teach a valuable lesson for human beings in this matter. In other words, more intelligent species have wiped out other competitors just to survive or to colonize certain places on earth. This is a very basic idea of how natural selection works and the examples of this animal behavior is out there if we look at history. For example, our ancestors in past brought the other form of our species to extinction just for the sake of food and shelter. Considering these survival needs, imagining aliens to be very friendly might sound too optimistic. They might indeed want to colonize earth and we might be just less intelligent form of life for them, nothing else. Therefore, it is considered to be dangerous to send messages into space.
In conclusion, although it might sound positive to communicate with aliens, if exist, we need to wait for while to develop so as not to fail if the war starts out with our newly found so-called intelligent friends