While this law was relevant when it was introduced, the make up of football crowds has changed and it has now become a family sport. A large percentage of football fans are women of all ages.
Fans of other sports can enjoy a beer while watching cricket, horseracing , rugby, etc. and do so without incident and I believe that the same would be true for football matches.
Most modern stadia now provide a relaxed and conducive environment where fans can enjoy their teams performance and for many that would include a pint of beer while watching the match. It must also be considered that the cost of policing matches is passed on to the fans in the ticket price. Increased security and CCTV coverage in Football stadia would ensure that there is no abuse.
I am sure that police officers could be deployed to more pressing tasks.