If you end up landing with less than 20% of your minimum fuel reserves there were some major planning discrepencies.
Well, it certainly means you were having a bad day but the planning may have been fine - I’m not privy to what information and fuel they started with. Until we have more detail it’s hard to say whether they were unwise or unlucky. At least they didn’t run out of gas and crash trying for an 8th approach.
Reserve fuel is there for a reason: the unexpected. It is very rare to get to the point of having to use any of it as normal procedures cover almost all eventualities but if we never ever expected to dip into it we wouldn’t carry it.
I can easily envisage a situation where the destination and alternate are forecast to be above minima but you take some extra just in case. You get to destination and it’s hovering around minima so you shoot a few approaches then divert just as your alternate does the same (unforecast) as the destination. By then you are committed to one or the other. The dilemma is whether to set off for your alternate hoping the weather improves or to stay where you are which gives you more chances to complete a successful approach.