Tags have levels, denoted by indentation. A tag ends when another of the same level begins.
Alienstrategy: is a first level tag, as it has no spaces before it. Simply delete from start of it's line, till the start of the next line with no starting space or tab.
In the case of the savefile I looked into, that would indeed be until the start of deadsoldiers:
The tags you listed are all the second level subtags of alienstrategy: in my savefile, so you probably did it correctly.