I see a lot of questions have their original tags deleted and then other tags added. I think we should leave the original tags of the questions if they are not offensive or have mistakes. I see massive deletion of tags and usage of other tags instead of them. 

Someone have made a tag and decides that his tag is better than new ones and deletes the new to use his tag. 

Isn't it better to leave people write what they want and at later stage when a good amount of tags accumulate then the users can decide which tags are synonyms. 

Maybe some of the new tags are better but we are not letting them evolve. 

By deleting a new tag only the opinion of one person is taken into consideration (the one who edit the question and deletes the tag). If for removing tags we use synonyms then removing a tag is by voting which of the tags is better and it is more democratic.