"but the Electra Glide may not be a stable enough platform for high speed pursuit"
Cops should not give chase on motorcycles. When a car and a motorcycle clash, the car will win. Always. Rather, the Harley is a perfect platform for an officer to observe the environment with ample space for accessories required for police work.
"Some European countries even have police version 999s. (Try outrunning that.)"
Easy. Ill outrun a 999 in a 1970 Toyota Corolla. How? Well I hit reverse and ride the cop off his bike.
"Reading sad stories like this one remind me of why some US police departments are opting for BMW police bikes."
BMW motorbikes immune to impact from a car? Dont think so. A rider of a BMW will be taken off the bikes as easy as any other bike.
"Police departments need to get the right tool for the job."
Harleys are perfect for the job. Low maintenance, low maintenance cost, good low speed handling, loads of room for accessories, part availability etc. etc.
"Harleys are great cruisers"
Yes they are.
"IMHO, they are not high speed pursuit vehicles."
No, and no motorcycle on the planet is. Helicopters and motorcars are pursuit vehicles. Motorcycles are patrol vehicles. Dont ever try catching a car whilst on a motorcycle. You may just succeed and end up dead or badly injured.