I believe the title of this post is wrong. A flu can be as dangerous as the covid virus. In The Netherlands, over 2900 people died from flu in 2018/2019 flu season. So, people who say "just" in combination with the flu, are not aware of the dangers related to real flu (a cold is not a flu).
Covid-19 is a virus and quite contagious and yes, you can suffer when you catch it or even die. So, just as the real flu, quite dangerous for some.
People should always have a choice about what they allow to be done to their body. Nobody likes it that others, like religious leaders and alike, try to control your actions. Same as with vaccines, People are free to chose. Not all people who have not been vaccinated yet are against all vaccines. Personally I do not have faith the the vaccines currently available. Once there is a vaccine that can convince me in respect to safety etc, I might decide to allow a vaccine.