In its nature, this is a bit like arguing that sober people can crash cars too, in response to drunk driving laws.
People with underlying issues - which can include managed conditions like asthma and diabetes - matter.
People over 50 also matter.
When you say the majority of children have mild to no symptoms, you're implicitly acknowledging that a minority of children have severe symptoms. They matter too.
Additionally even children with initially mild symptoms can have long-term problems. Those children also matter.
The people children can pass Covid-19 onto also matter.
Those people also include everyone who isn't 50+ or a child who can also have a severe illness, long-term symptoms, or even die despite not having underlying conditions. You seem to think if they're not a majority they don't matter. They do matter.
And the people who can't get treatment or have critically delayed treatment for non-Covid illnesses or injuries because the healthcare system is overloaded with Covid patients also matter.
And the most focus is on the most vulnerable (hence their being typically vaccinated first), the rest of the population is monitored, and there is vast amounts of real research being put into Covid and long Covid. And we also vaccinate as part of all that. Because vaccinations are one of the most powerful and effective tools at our disposal.
You'll get clown responses because if you took a moment to step back and think about it, you might realise your questions and concerns are those of someone who plainly hasn't taken a moment to actually, critically, think about what they're saying.