The problem for the MetO is that their warnings are used by a lot of people and should they start being more gun-ho about issuing them, how long will it take till some people think a "Red warning" is just some "Health&Safety gone mad", ignore them and end up in a dire situation? As a specie, we do tend to become quickly immune to "Wolf" cries... You then also have the problem of businesses taking heed of alarmist warnings and then turning against them with accusations of ruining business. If they issue a Red warning for, say, Cumbria for the week-end and it turns out it's just a stiff breeze, you'll have a lot of people in the tourist industry very upset with them
It's a difficult call really and that's not seeking excuses on their behalf, they messed up and they know it.