You're 39. That means you're old enough to ignore things that are written that you don't agree with. Unless something or someone is physically hurting you or writing libelous content about you, it's usually better to just move on and ignore it.
Technically, boomer is a synonym for old. Anyone who is part of the boomer generation was born at the latest in 1964 and as early as 1946. That, my friend, is old. Someone born in 1964 would be at least 59 at the youngest age and 77 on the older end.
No, technically "boomer" designs people born during the baby boom era after the war up to mid 60's. that's it!
Calling a 50yo or even 40yo a boomer is plain stupidity exposed.