Someone who is mentally ill is unlikely to finish their education successfully, likely to take up a variety of pastimes to try and have a community (like streaming, posting online to find social interaction), and probably has poor risk assessment skills due to their illness. You just described what it looks like to have early schizophrenia or ADHD, to an absolute tee.
Mentally ill people are allowed to be upset at the world. They’re allowed to make criticisms while being people who aren’t necessarily ‘on top of their shit’. Grow up and become less judgmental of the individual, and more keen a listener for what isn’t being said so clearly.