If it gets insane you could always try what i suggested in that other thread, namely;
You could try the suggestion I gave someone earlier this year, minefield your shipping lanes untill those civs go bankrupt, or blast them apart with lasers[], I think someone mentioned it was possible to directly target your civilians.
Maybe even missiles if that's possible.
1) Design a long range very fast missile with a huge thermal sensor
2) space master in a PDC with 100 tubes and a large magazine, also fire control and active sensor if that kind of thing floats your boat
3) under individual ship window use the "Missile launch button"
4) profit (design some salvagers and put them to work, if you don't think it's right to use the extra resources just dump them on a rock somewhere)
I think i'll go do this in my test game.
Observations
1) given enough subsidy a shipping line will launch a new ship every 5 days.
2) despite having 100,000 in the bank the company will still build small ships, perhaps it wishes to diversify it's investments?
3) Turns take a while to process with 10 lines launching new ships every 5 days, even with only 25 ships actually in space
4) random error 6 overflow (error in return date) happens whenever i open the economics window or specifically click on earth there.
5) Wealth is only at -100k despite spending a million on the lines, Wealth/trade does show that I spent a million on subsudy in the last year.