While I agree there's not much point in getting upset over teenagers on Tumblr being melodramatic or rude, and particularly not with the power differential in your scenario, I have to question "Tumblr is comprised mostly of people under the age of twenty."
Tumblr has a reputation as a site for teenagers, but the demographics don't bear that out. All the demographic stats I've been able to find have been that 50-60%+ of Tumblr users are over 24 (most of them college-educated, but not high-earning). A significant percentage are under 35, and certainly there's a large minority under 20, but I honestly don't think the generally hostile climate of parts of Tumblr can be explained by it being a teen-dominated site, because it's not.
no subject
Tumblr has a reputation as a site for teenagers, but the demographics don't bear that out. All the demographic stats I've been able to find have been that 50-60%+ of Tumblr users are over 24 (most of them college-educated, but not high-earning). A significant percentage are under 35, and certainly there's a large minority under 20, but I honestly don't think the generally hostile climate of parts of Tumblr can be explained by it being a teen-dominated site, because it's not.
Sources for demographics: http://brandongaille.com/26-astonishing-tumblr-demographics-trends-and-stats/
http://www.quora.com/What-is-the-demographic-breakdown-of-Tumblr
http://www.theguardian.com/media-network/media-network-blog/2013/jun/20/brands-know-tumblr-users-infographic