"Now ere those weapons to cause the instability or cure it?"
Neither - they were to make money - these sales were for profit and no other reason.
THat is what makes the Arms Trade no better than the illegal drugs trade - no consideration is given to the human effects of their distribution
The risk of terror threats to Britain or elsewhere is a bonus!
"If good people did not sell arms to good people"
As crass as it gets when you consider who these arms are being sold to

The "good" recipients of British arms
Saudi Arabia, which has been accused of perpetrating war crimes in Yemen.
Bahrain, which used troops to quell protests following the Arab spring.
Burundi, which is being investigated by the UN for human rights violations.
The Maldives, which in 2015 jailed its former president, Mohamed Nasheed, for 13 years following what critics said was a politically motivated show trial.
Figures shared with the Observer show that in 2014 the UK licensed just £170m of arms to 18 of the 27 countries then on the "priority countries" list. The massive increase in sales was largely attributable to sales of weapons to Saudi Arabia. The largest export licence granted was for £1.7bn of fighter jets, agreed in May 2015. In July 2015 the UK approved the export of £990m of air-to-air missiles. In September, it approved the sale of £62m of bombs to the country. All three sales took place after the bombing of Yemen began in March 2015, prompting concerns that civilian buildings have been targeted in widespread human rights violations."
Jim Carrroll