That's too vague. Free software is software you can't take and then modify and keep your modifications hidden or proprietary, thus depriving your users and the community of access to these changes.
MIT license allows this, hence it's not a free software license. Because very large corporations don't like freedom they've poisoned the discourse around software freedom and launched PR campaigns trying to substitute talk about freedom with talk about openness or open source. To some extent they've succeeded, as evidenced by the chatter about it in this thread.
Are you actually unaware of this? If so, why? Is it age or have you been sheltered somehow?