What is the idiom for a guy/situation who/where has his own shortcoming but still mocks others?

What is the idiom for a guy/situation who/where has his own lacking but still mocks others?

Like you are poor but you laugh at a rich man who has just become bankrupt.

For example, suppose like this "A drainer mocks at a needle".

Explanation: A drainer has hundreds of pores, but he is mocking at needle's only one hole.

Consider, people who live in glass houses shouldn't throw stones

One who is open to criticism should not criticize others. This proverb is so well known that it is often shortened. [Late 1300s ] Also, It's the pot calling the kettle black Random House

From Bible:

Why do you look at the speck that is in your brother's eye, but do not consider/notice the beam/log that is in your own eye?

What gave many variants, for example:

to see the twig in somebody else's eye and not pull out the big log in our own eye".

Another one is :

it's the pot calling the kettle black.

Which is an idiom used to claim that a person is guilty of the very thing of which they accuse another.

If it were a rich man laughing at a newly-made bankrupt, it would simply be spiteful, but the usual word for seeing someone brought down (especially to one's own level) is schadenfreude.

Pleasure derived by someone from another person’s misfortune:
a business that thrives on Schadenfreude
a frisson of Schadenfreude

[ODO]

It's borrowed directly from German, derived from Schade (harm or shame) and freude (joy).

You might say that this person is suffering from the Dunning-Kruger effect:

The Dunning–Kruger effect is a cognitive bias in which relatively unskilled persons suffer illusory superiority, mistakenly assessing their ability to be much higher than it really is.

The "see also" section of that Wikipedia page also contains some terms that might apply:

• Overconfidence effect
• Self-serving bias
• Superiority complex

I think that the idiom you are looking for is the pot calling the kettle black.

I think wikipedia defines it well:

The phrase "The pot calling the kettle black" is an idiom used to claim that a person is guilty of the very thing of which they accuse another.