Why did he say I was lying?

At work we hve a new boss and it was me and this guy and the boss just chatting and working and the boss said i look like a gurl who likes to read in my free time ir soemthing quiet ab1d peaceful. I agreed that yeah i like reading.
Then this guy said "she lying"...* i ignored him.

But im like, whaat, in my head like is he saying i seem too dumb to read books?
Why did he say I was lying?
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