These are not differences, these are similarities. Think about it for a second. Soviets had you register with the police where you were going, because there was no centralised database with that information. Today, the US government achieves exactly same result, but without making you go to the police station to register. Wherever you go, they can access your location on your phone, read your licence plates with street cameras,and do automatic face recognition in many cities. Do you see how this is a similarity, rather than a difference now?
The same with passports - they don't need to hold on to your passports, because they can just block you from going out of the country using a centralised system. Also, they can block you from coming back to US by placing you on a no-fly list, without any explanation - making you take a very long and expensive ship journey.
Telephones - soviets would openly monitor your phone calls. US government does it from hiding, not telling you that you might be wiretapped. Again, different method = same result.
Letters and Parcels - only letters are protected, parcels can be opened at anytime by any postal office worker, if they have a "reasonable" reason to.
Censorship - not done openly in the US, but again - there is no need for it. They keep everything you write saved for future use, so even though you can write whatever you want on your blog, it can still be used to prosecute you. It effectively is censorship in my opinion, even if it's not censorship per se.
They aren't similarities. The fundamental goal is different.
Registering where you're going, warnings that the phone call is being recorded, those things are about FEAR. It's deliberately letting you know that the government is in the driver's seat and you shouldn't even get started with counter-revolutionary thoughts. The information gathering is secondary.
Tiananmen square has probably more than 1 video camera per square foot. That's not to get better footage, it's to send message.
There might be a day when the US is the same, and this might even be a critical moment on the way to that day, but right now the fact that the US is trying to hide it's intel capabilities as opposed to rubbing them in your face makes them categorically different.
The same with passports - they don't need to hold on to your passports, because they can just block you from going out of the country using a centralised system. Also, they can block you from coming back to US by placing you on a no-fly list, without any explanation - making you take a very long and expensive ship journey.
Telephones - soviets would openly monitor your phone calls. US government does it from hiding, not telling you that you might be wiretapped. Again, different method = same result.
Letters and Parcels - only letters are protected, parcels can be opened at anytime by any postal office worker, if they have a "reasonable" reason to.
Censorship - not done openly in the US, but again - there is no need for it. They keep everything you write saved for future use, so even though you can write whatever you want on your blog, it can still be used to prosecute you. It effectively is censorship in my opinion, even if it's not censorship per se.