In addition to capturing and storing still images and video, your camera has some "built-in editing features". It also stores various meta-data information related to the captured stills and video. In order to do this, the cameras needs to have something that can keep track of that information like a database. To maintain that database, an embedded "operating system" in the camera is needed.
When the camera captures the still image or video, it knows to update the database. When the camera deletes or otherwise modifies the still image or video, it knows to update the database. When the files are moved or modified or deleted by a computer, the database in the camera is not updated the camera's operating system can't find what it needs and things don't work - leading to the "corruption".
For the most part, all half decent modern flash memory or hard disc drive consumer cameras and camcorders operate this way - this is not specific to Sony. They are not "personal media players" and are not designed to be used as a USB mass storage device anyway you want. They are "purpose built" electronics that are designed to efficiently capture, maintain and store still images and video (though video is a secondary convenience feature) and use the built-in editing and tracking features.
I suppose the same could be said about the start-up drive in a computer: if you move the various system or preferences files around to your liking, the BIOS (or rest of the operating system) won't know where to find stuff and the computer startup will fail. This is not the computer's fault.
As for "some photo programs cannot see/show the photos until after they get transferred to computer too. They see the camera as a drive and see the folders but say there is no photos in the folders. Once I transfer the photos to pc then programs can see them" - since we don't know what applications you are using, it is impossible to provide specific assistance. It is possible the Sony app you use can deal with the camera database while these other apps cannot. That is not much different from Microsoft Excel not being able to deal with an OpenOffice spreadsheet file type... Each manufacturer is trying to capture and maintain their "customer base" by using different methods.
You have set an expectation that the camera was not designed to do. Since you did not design it and there is currently no way to change/hack the camera's design/firmware/embedded operating system, you have a choice:
1) Design your own camera operating system and get the firmware built and installed into the camera (like Magic Lantern has done for certain specific dSLRs);
or
2) Pay someone to do the design and implementation of the new firmware;
or
2a) Go to work for Sony and change it;
or
3) Use the camera (and process flow) as designed/suggested;
or
4) Don't use the TX20 or any other similar device;
or
5) Use the old Sony device instead. Since we don't know what it is/was, we have no way to know if it is as sophisticated as the TX20.
Please keep in mind: Your purchase and continued use of Sony products rewards them and tells them they are doing the right things... They can't read your mind.