You are correct. Most times, the proper word would be the adverb "personally" vs the adjective "personal. However, depending on where one grows up; certain colloquialism and forms of language is common and acceptable. It is acceptable to describe a person with an adjective and say they took something "personal'; which describes THEM as someone who thinks people are picking on them. Vs using the word "personally" to simply say they are reacting to a situation and internalizing it.
This is also common when using slang, street talk, etc... Grammatically, it can be correct or incorrect. Depending on the meaning. As much as some people don't like it, AIN'T, is an "acceptable" word.
But what's more important, is that I never once said anything about anyone's "GRAMMAR". I simply mentioned using the WRONG WORD when writing. Big difference. The English language is one of the most difficult. Especially with all it's homonyms. I simply pointed out that many people were using the wrong word. Not incorrect grammar, spelling, etc... Just a word that didn't mean what they wanted it to me.