So like the Taliban you think all music should be banned,interesting. Oh and Data sang and played musical instruments in several episodes so why don't you have this deep seated personal hatred of him.
You know nothing of computers so you can't say what is possible. If Data could be programed to do it when he was made by one man on a backwater planet almost 40 years before how is it so hard to believe that a team of people working in a state of the art lab with unlimited funds couldn't do the same thing when they had more advanced and bigger hardware and software to work with? Also Data learned new things over seven years so how is it impossible that Holodoc could learn new things in the same time? Data's personality and everything he knows comes from software just like holodeck character. The software is stored on hardware but it's the software that makes things work. Look at the computer you are using right now,if you take all the software off of it then it can't do a thing and that is how Data would be without software. Remember we saw a few times when his memory was wiped and no hardware was involved and just like a Holodeck character Data couldn't remember what had happened to him so he is software in a body just like them. Oh and remember when Data downloaded his daughter's memories,he didn't have to attach her body to his,if androids are hardware then he would have had to walk around with her head on top of his but he didn't do that he downloaded he memories. if you know even the most basic think about computers and what they can do then you know that only software can be downloaded,not hardware. Oh and how is it more believable that software could be made for Data then it could be for a holodeck character. Oh and in season one of TNG Holodecks were brand new,are you saying that technology never changes or upgrades because Vic and the Doctor were created more then a decade latter by people who had been working on them all their lives. You are saying there is no way that the holograms could have been upgraded? You have in fact stated that at no time in human history has any computer program ever been updated or improved. You have stated that it is impossible to ever improve technology. Well I have news for you my $100 cellphone now has more memory,processing power,and a more complex operation system then the $700 desktop computer that I had a decade ago. That is how fast things have advanced in a decade. It is not impossible as you stated,it's part of our every day life. Also the early Holodeck characters could become self aware by themselves so how is it so hard to believe that someone could program them and do on purpose what had been done a decade earlier by mistake? If you don't believe science can discover new things and solve new problems I really don't think your problem is with these characters but with Star Trek in general.
Oh and please don't try to tell me what is possible with computers,I have built four computers from the ground up and watched AI being programed for games. So I have a very firm grasp on what is possible and how computers work. Oh and try to remember how far computers have come just since the early 90s and remember that Star trek is set more then 300 years in the future. Many people didn't think that the things computers can do today would ever be possible just a couple of decades ago when they were running off of DOS. Remember this is a future where kids learn advanced algebra in second grade and the computers can hold a human brain if needed,these are very smart people using very advanced hardware and software.