Upvote:9
No they have no obligation. Visa requirements are highly complicated and depend on many factors, not just which country issued your passport. It is your job as the traveller to understand whatever visa requirements or other restrictions as they apply to you individually.
Incidentally, you did not need a visa if you were arriving on an international flight at Sydney and departing also on an international flight, with less than eight hours in between, under an ordinary UK passport endorsed "British Citizen", and you did not intend to leave the international zone in the airport (for instance to collect bags). If you have a different type of UK passport (such as "British Overseas Citizen" or "British Protected Person") then different restrictions may apply. If your transit actually included domestic travel inside Australia or you needed to recheck your bags, then you could have applied for an evisa (subject to certain requirements) online and this would likely have been approved within a matter of minutes.