NFL Training Camp: Rules??

QUESTION:  How can NFL players (defensive, offensive, or special teams) complain about the new game rules when they agreed to the Collective Bargaining Agreement terms below regarding training camp?

WOW!!!

Article 23: Preseason Training Camps
Section 6: Conduct of Practices:
(a) The first day of a Club's preseason training camp shall be limited to physical examinations, meetings, and classroom instruction; no on-field activities shall be permitted other than running and conditioning. No contact shall be permitted and no pads shall be worn during the second and third days of Preseason Training Camp. Thereafter, two-a-day practices shall b e permitted, subject to the following rules: (i) players may be on the field for a total of no more than four hours per day; (ii) players may participate in no more than one padded practice per day, which shall be no longer than three hours of on-field activities; (iii) there must be at least a three hour break after the practice; and (iv) the second practice on the same day may only be for a maximum of the remaining available on-field time, and shall be limited to only "walk-through" instruction (i.e., no helmets, full-speed pre-snap, and walking pace after the snap). The three-hour limit on padded practices shall begin as soon as position coaches begin to coach players on the field. The definition of a "padded practice" under this Article shall be the same as the definition used for regular season practices in Article 24, Section l (c) of this Agreement. In the event that a Club begins a padded practice but such practice is cancelled within sixty minutes of its commencement due to inclement weather or for any other reason beyond the Club's control, such practice shall not count as a padded practice under this Article or Article 24.
(b) Notwithstanding the foregoing, or anything in Article 24, it shall not be a violation of any provision of this Agreement pertaining to the prohibition or limitation on wearing of helmets or shoulder pads, nor shall it constitute a "padded practice," if: (i) quarterbacks, kickers, punters, and/or long-snappers only wear helmets and/or shoulder pads during practice at the option of the player; (ii) a player who, because of a head injury, is directed by the Club physician to wear a helmet as a precautionary measure at all practices; or (iii) the quarterback and/or the defensive player who receives signals from the coaching staff via helmet communication wear helmets during the team period in which helmets are used for such communication.

And, for reference:

Article 24: Regular Season and Postseason Practices
Section 1: Practice Rules
(c) For purposes of this Article and Article 23, a "padded practice" shall be defined as a practice in which players are required to wear helmets and shoulder pads, in addition to any other equipment required by the Club, subject to the exceptions set forth in Article 23, Section 6(b).