The same reason you don't hear ultrasound sensors of cars when backing up. Microphones can only capture a certain frequency range, but you can still hear/feel those waves when they hit you
dust_accelerator
It's very subtle, and official travel recommendations have been updated to reflect the possibility of trouble when your passport details are not perceived as consistent. The public services move slowly, but anyone I know that this would apply to has long understood the language and has opted for avoiding travel to the states. It's not like your life is ruined by not seeing Orlando ยฏ\(ใ)/ยฏ
I feel this is a lack oft creativity. Protests need to be peaceful, but disruptive. In a car based society, protest by car? If 5,000,000 cars "meet up" in any given metropolitan area, that areas productivity goes to zero, those in power won't even have any recourse, there aren't enough police/towtrucks to counter this, and if so it would take days or weeks. Only coordinated driving and parking/traffic jam required.
Effective protest should instill fear in those in power - the message is, with the sheer number of people right outside your building, could easily crush you if they so choose. A few guards can not offer protection in this case. The idea is, with this realization, that violence is not a good escalation, as in the end the powerful few will never come out on top.
This only works if the powerful few actually believe the masses will go as far as needed to effect the demanded change.
From outside, it appears the US protests favor comfort over conflict, thus are viewed as lacking credibility and therefore, pose no danger to the power class. As long as the individual prioritizes their selves before acting as a collective, including taking the risk of collective punishment, the protest remains unbelievable, therefore ineffective and easily ignored.
Fairphone 5 on /e/os checking in. Works great as well