They can be purchased from the vendor "Veteran Crusader Aliocha Segard" (NPC ID 30431) located at The Argent Vanguard, Icecrown (87, 75). However, they still require the original pre-event currency (ID 1754) which I don't think it is possible to get more since the event concluded.

For example, the Anti-Doom Broom is marked as "removed from the game". Yet it can be purchased from this vendor, with the original price. The wording should indicate its current availability.

Crusader Adevald Ironbeard (NPC ID 173791) at the Argent Tournament Grounds states the current availability correctly; this should be reflected on the items:

While these are 'available' to purchase, the currency by which to purchase them is no longer available to obtain. By our standards, if the sole means of obtaining a 'Thing' is removed, then effectively obtaining that 'Thing' is also removed.
If you enable the proper Unobtainable filters or toggle on Debug mode, you will see all the proper associations and data for these items.
But we are not going to mark something as available when they are technically not available without meeting some pre-existing condition that is no longer available.