At this time, streaming TV services like YouTube TV, PlayStation Vue, DirecTV Now and others like it don't have to carry channels under the must-carry rule. The same channels normal cable companies and satellite providers have to carry. In short, this means channels like PBS isn't included in many to any live local TV streaming service like YouTube TV.

By signing this, you will be telling the FCC that you want live multi channel TV streaming services like YouTube TV,  PlayStation Vue, DirecTV Now to be counted under the must-carry rules.

If you're interested in what is the must-carry rules. The following is a wiki link to the talked about rules.

https://en.wikipedia.org/wiki/Must-carry

If you're wondering why places like PBS just don't jump on these other platforms. The following is from the Wiki link.

In the U.S., retransmission consent has often been chosen over must-carry by the major commercial television networks. Under the present rules, a new agreement is negotiated every three years, and stations must choose must-carry or retransmission consent for each cable system they wish their signal to be carried on. Non-commercial stations (such as local PBS stations) may not seek retransmission consent and may only invoke must-carry status.