you could first ask the strata committee and then the agent … which insurer was chosen and why.
“Because they offered the best cover for the premiums demanded,” would be the easy answer to that, and hard to disprove.
But to expand on your initial point, owners are entitled to see all strata records and the strata manager is legally obliged to show them (usually at their office for a modest fee).
Also, in NSW strata managers must declare any commissions they make from arranging insurance cover.