A user needs to have a reputation of 10 or more to "Use images or many links to posts":
If that were changed to "Use images or links to posts", it's possible that spamming may be reduced. In other words, a user with less that 10 points would not be able to include a functional link in a question or answer.
There are many measures that could help fight spam but which are not done because they would be much more harmful to legitimate users. This is one of them. Other harmful ways to help fight spam might include:
requiring all users (or all new users) to complete annoying CAPTCHAs for any action
requiring all posts to be reviewed privately before appearing publicly
making a single spam flag delete a post
using heuristics to automatically and randomly delete posts which have a calculated 50+% chance of being spam, after an unspecified delay, and to hellban users who might (or might not) be spammers
Compared to the problem of low-quality legitimate questions and answers, the problem of spam on our site is minuscule. It would remain comparatively tiny even if it increased by an order of magnitude.
So any proposal that makes it harder for people to post good questions (and answers) is something we should not implement. In particular:
We should make it so posts only rarely need editing to be immediately and easily understood by everyone. This is why we allow people to post two functional links even if they have <10 reputation.
We should encourage people to provide as much documentation in their questions as possible, and as much citation in their answers as might be helpful. Any measure that makes this more difficult both directly prevents people from creating good posts, and sends the message that we do not really care about quality.
We should make it so that using Ask Ubuntu does not require special technical skills. This is why we allow easy linkification, and for URL's automatic linkification, even for users that have <10 reputation.
Users should not have to fight the system in order to use it properly. Posting deactivated links constitutes, as Braiaim has commented, a way of circumventing the system. It may not be universally wrong to tell people how to circumvent the system, but we certainly shouldn't redesign the system to make circumvention necessary or common!