Some are but most aren't.
Gay guys do not have a high pitched voice any more than straight guys do. The tone of one's voice is not related to one's sexual orientation. I am gay and sing bass in a chorus. I know a straight man who is frequently called Ma'am on the phone. You may be talking about some gay men speaking in an effeminate manner. This is learned behaviour and most gay men do not speak that way.
because gay peope only likes to sing or paly in instrument
Sing Another Chorus was created in 1941.
Chicago Gay Men's Chorus was created in 1983.
Connecticut Gay Men's Chorus was created in 1986.
Portland Gay Men's Chorus was created in 1980.
London Gay Men's Chorus was created in 1991.
Gay Men's Chorus of San Diego was created in 1992.
Johnny 3 Tears, J-Dog, and Deuce sings the chorus and one other verse.
San Francisco Gay Men's Chorus was created in 1978.
New Hampshire Gay Men's Chorus was created in 1998.
Gay Men's Chorus of Los Angeles was created in 1979.