I don't want to be pedantic because I appreciate your astute analysis, but as a fan of classic movies, it's clear that this isn't an ad, but rather a t-shirt referring to a humorous line from Legally Blonde.

• The line was famously said by Jennifer Coolidge's character, Paulette.
• Closer inspection of the image reveals that it is printed on lightly wrinkled fabric.
• There is no brand being advertised.

Unfortunately, the composition of the photograph omits the sleeves and neck of the shirt, and the design evokes the imagery and aesthetic of advertisements for 1960's drive-in theater concession stands, so it is easy to mistake it for an ad.

Ultimately, the main point of your comment, that the phrase is still difficult to read even though the words "Hot Dog" are grouped together, still stands.

Which then does work for this post...