As do I.
For one thing, the so-called free speech zones weren't limited to presidential appearances. They were in use throughout the conventions (and will be again this year). Secondly, the treatment of the two parties at the conventions sends a very clear message and demonstrates a desire to sanitize the whole thing; put the people with the ugly signs 2 blocks away where they're out of sight/out of mind.
I think the last part you mention takes it too far (I've never defended that, and have made quite clear
from the beginning that this was my position) - but I think justified action to defend the President's life would contain many of the sanctioning and general "quarantining" that is in this bill.
And let's not pretend that the President is a normal citizen. It's a democratic fantasy, simply being the head of the government makes him more of a target than a normal citizen -
and he has to stay and be a
public figure, whereas most of us a private citizens. And the President being killed has huge political and social ramifications. Just look at the consequences of assassinations in history. In a Democracy, it martyr's the President, and any movement he's associated with.
The conventions are basically a huge symbol of our political systems, their time, date and places are known well in advance. This makes the conventions a much larger target for attacks, and so it needs stricter and better security. It's not like the President's normal trips, which are kept rather secret from the public. If this was out of a desire to stifle opposition, wouldn't it be done more, contrary to what you said - and doesn't the fact that it's not often indicative of a motive to keep someone safe?