Is not based in brainfuck, its a turing machine, and both look that way because any less instructions are not enough for programming a digital computer.
Converting from groot to brainfuck requires simply a 1-1 command translation. It doesn't matter if these are turing machine operations, the point is that there is nothing 'esoteric' about writing down what a turing machine does using a language that everyone already knows.
If I rewrote C to use BEGIN and END instead of { and }, then that's not inventing an esoteric language, but new syntax for an existing language.
The type of abstract syntax trees of this language and brainfuck are isomorphic. There are lots of definitions of what a "Turing Machine" is. If we take the one on Wikipedia as canon it isn't the same as this.
In particular, a Turing Machine is a model while both Brainfuck and Groot are languages. It's easy to see how each of these languages is directly translated into a Turing Machine model (providing them a choice of semantics). Indeed, due to their isomorphism we need only translate one of them to have a faithful translation of the other "for free".
Better yet, Brainfuck and Groot both have a privileged semantic model which is more or less identically a Turing Machine (except Brainfuck merely specifies that the tape is at least 30,000 bytes long and Groot mentions site not at all while Turing Machines are explicitly infinite).
So, they're really closely related to a Turing Machine but honestly separate things more closely related to one another (via isomorphism) than to TMs directly (via semantic mapping).
If I rewrote C to use BEGIN and END instead of { and }, then that's not inventing an esoteric language, but new syntax for an existing language.