Here is a fair assessment which describes him as hitting and then clutching. This content is protected It still doesn't change my opinion of what would happen between him and Fury who would negate him the size advantage.
Assessment is incorrect. Johnson is controlling his opponent not clinching or clutching. His opponent is free to punch but Johnson renders/ absorbs the power of body blows by touch/pushing their elbows. Punches to the head are blocked. Watch very carefully his bout with Flynn. Flynn lands body blows but he can obtain little leverage. He tries to bring punches to the head but they are artfully blocked. Flynn complains about holding but the refs statement after the bout was that "Johnson was not holding. Flynn was free to punch". If you watch carefully that is exactly what was going on.