The GPL imposes conditions on your use of the code / program, as does the MIT License. If you don't follow the conditions then you do not have a license to use the program / code & are open to claims of copyright infringement.
You might choose to ignore the licenses on the code you use, but it certainly isn't a great idea in a commercial context (and in your personal projects probably just a moral dilemma). Although, sadly, I'm not sure any of the many public GPL violations have really "cost" the companies that did them all that much.
Edit: I guess you're saying, yes, you can just go ahead and use it. Which I guess is the position large LLM training corpuses have taken ..