Why are genes for rRNA and tRNA considered to be genes even though they do not produce polypeptides?

tRNA and rRNA are ALSO GENE PRODUCTS along with polypeptides.

Explanation:

Gene is the totality of the sequence of nucleic acids involved in the synthesis of a functioning polypeptide.

Apart from the nucleotides that code for amino acids of proteins, there are other types of gene that codes for RNA transcript, that is, the rRNA, tRNA ).

Transcription of these genes do not encodes proteins but during the mutation of those genes, specific phenotypes can be formed.

rRNA and tRNA are gene products and are categorised as genes.

yes, because even though a theory has a  lot of evidence to support it, it is not always true