Why are they giving Covid 19 vaccines to seniors citizens(over 70)?

Because, believe it or not, 'some' people actually think that our lives still have some value.

Those people to whom you refer, the over 70s, have probably put more into society than you younger ones ever do or will ever even want to do.  We all had responsibilities and accepted them. There was no skiving, staying in bed all day, giving cheek to parents and teachers. 

We had to be absolutely obedient, pull our weight and be courteous and caring.

Having more life ahead of you does NOT make YOU more valuable than those over 70.  We have the knowledge, the work ethic, the good manners etc. that many of your generation lack.  Your own children are going to enter a world with no ethics, no decency no pride in their work etc. and a time will come (when ALL we oldies are gone) when you, and others like you, will not know to whom you can turn for help and advice and, only then, you will realise what you have missed.  I pity ANY kids that YOU have or will have.

Seniors have a right to live too, you stupid imbecile.

I'd love to see you tell your grandfather, 'Sorry YOU are too old for a vaccine. I will just let you die, since I am younger.'

That might be true, but they say that the vaccine may be too strong for the younger generations. Most Seniors in that ages bracket can live a longer life if they take care of themselves better. That included you too.

Enjoy your life while you can.

The elderly are more susceptible to the virus and could spread it more readily. Also, the elderly have just as much right to live a health life as the young!

Because, we the elderly, are more frail and are likely to die from this virus than are younger people.  One other way of looking at this might be that the elderly have put far more into the world and their own society than the younger ones have. We've all worked hard, not skived, lived very decent lives (most of us!!) etc and deserve to remain healthy for as long as that is possible.

It's sad to read questions like this one because it just seems to add to the evidence that many of the young just don't care about the elderly.  We are useful when they want a handout or a favour but, otherwise, we are dispensable.  How sad is that?

We are the most vulnerable cohort of the population. Obesity, multiple comorbidities and all that.

Because young people, unless they are in poor health already, will not die from covid.  Over 70 it is more likely.

The young HAVE more life to live, you meant. They're giving the vaccine to seniors because the virus is more dangerous to seniors. Are you going to pretend that you weren't aware of that, Steve?

Because the risk of fatalities is so much higher than it is for young'uns.