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.
As a end user, I find it quite restrictive. There might be some software I won't be able to fork/modify because they were MIT. I'm not the owner of the software anymore.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons..."
The MIT license always allows you to fork/modify the project. You wouldn't be the copyright owner of the existing code in your fork, but you could be the owner of the project, and the copyright owner of any new code you add.
