Question

‘Einstein did not know what to do with other children and his playmates called him ‘Brother Boring’. He played by himself and especially loved mechanical toys.

Why did they call him so?

Answer 1

The answer is already in the question...

It was because he played by himself and loved mechanical toys

Answer 2

they assumed that he was boring as he was not like others he did not play with other children,

he used to play alone