Who is a whiner?

[_______________North]

A person can be dissatisfied when...

dissatisfied
not pleased with something; feeling that something is not as good as it should be.

When dissatisfied people usually like to state

opinion
(one of) the ideas that a person or a group of people have about something or someone, which are based mainly on their feelings and beliefs, which is also a judgment about someone or something.

There are a lot of people who like...

argue
to give the reasons for an opinion, idea (a suggestion, thought or plan for doing something), belief (the feeling of certainty that something exists or is true)
, etc.
(=gives reasons for and against something in a clear way).

In this case, people have right to...

support (encourage)
give encouragement and approval to (someone or something) because they want them to succeed

and people also have a right to...

disapprove
feel strongly that something or someone is bad, wrong etc.; not to approve.

They can use different means...

discourage (make less condident)
to make (someone) feel less confident, enthusiastic and positive about something, or less willing to do something

However, the problem is mostly with...

whiner
those persons, esp. childs, who like to complain or express dissatisfaction continously.

Stating an opinion is not whining nor is arguing against it.