A person who denies things can be referred to as a "denier." This term is often used to describe someone who refuses to accept facts or reality, especially in relation to controversial topics, such as climate change or historical events. In some contexts, terms like "skeptic" or "contrarian" may also apply, depending on the nature of the denial.
What to say to a person who criticizes another for having the same problem they have but denies it.
A person who makes of
collecter
A person who looks on the gloomy side of things is pessimistic.
A person who builds things out of stone is called a stonemason or a stoneworker.
A person who hoards things that you have would be called..."you." Or whatever your name is.
Antinous is the person who denies food to Odysseus during the feast in book XVII of the Odyssey.
You could call them generous or a recipient or a patron.
An idiot.
A snuggler
Smart
A husband