Fire hazards are a huge problem, and no one can completely eliminate the threat of fires no matter how careful they are. I believe making building materials more fire resistant will cost more money when building the building, but it will cost much less when there is an actual fire and I believe insurance for that building will be lower.
Yes, I believe that building materials should be required to be as fire resistant as possible, especially for large public buildings that thousands of people pass through each day. When you enter a building, you have no way of knowing it the materials are fire resistant or not, but we all deserve safety.
There is plenty of new technology that makes it easy and cheap to make fire-resistant building materials. People who put up buildings don't want to use them because it cuts into their bottom line, but at some point we have to declare that the safety of citizens is more important than profit.
No, not all building materials need to be more fire resistant. The degree of requisite fire resistance should depend on the tow of structure, where the structure is located, and what the environmental and economic cost is of creating fire proof building materials. Some regions are not particularly prone to fires and it would not be worth the cost.