Ignoring what is hopefully sarcasm on the empirical part, it's a double standard because it assumes that saying Obama sucks must be a dogwhistle and tied to undertones of racism.

"Dogwhistle

The phrase "Obama sucks" can be interpreted as more than just a simple critique of a political figure; it has been used to express racist sentiments by implying that a Black president is less capable or worthy of respect. This reinforces harmful stereotypes and can contribute to a broader culture of disrespect and division."