If anyone does not know what is meant by "dog whistle" politics here is a blatant example of it.
Republicans are masters at it and employ it often just as you see here.
The intent of this video is to suggest that all or most Obama supporters are uneducated unemployed minorities on public assistance.
Dog whistle politics attempts to be effective by suggesting and/or reinforcing negative stereotypes in the minds of viewers or listeners that are often racist and xenophobic.
Bravo to the OP. You've learned well. You must be proud of yourself