the context of some verses

[shaad_lko]

he used to be better when he joined here - but maybe patience is not a virtue in everyone..

[Al-Boriqi]

If these verses were meant to be concerned about self defence, why doesn't it say something like - fight those that fight you?

It does. The entire basis of the surah was in relation to those who made war against the Muslims.

Instead it talks about attacking the non-believers. No mention of "mischief".

The entire suratu-Taubah, the ninth chapter of the Qur'an is in relation to those who are in war with Muslims. The correct understanding of the entire surah is based on another ayaah in he Qur'an where Allah said

It is only as regards those who fought against you on account of religion, and have driven you out of your homes, and helped to drive you out, that Allah forbids you to befriend them. And whosoever will befriend them, then such are the Zalimun (wrong-doers - those who disobey Allah).
( سورة الممتحنة , Al-Mumtahana, Chapter #60, Verse #9)

Also why isn't there a context of a time limit?

if you would actually read, the time limit is the moment that the disbelievers concede to a peace treaty. Apparently, the disbelievers were to barbaric for peace.

Historical context: It was decided that non-muslims not be allowed in Mecca. People were worried that money flow would decrease so jizya was initated.

the historical context is what I highlighted above. As for this, this is no context at all