Why do resistances work the way they do?

Many sets, as you know, come with natural resistances. For example wearing a vog cub set gives what it seems to be a maximum fire resistance. I know that the bar limit is not really a limit since values can go beyond it, but this is not what this thread is about. What's important here is that having a full fire resistance bar with vog cub set is the same as having any other non fire-resistant set with two lows fire uvs, and this works for any resistance and any set. Why? I mean, WHY would you do it this way? A low resistance uv is only like half a bar while a natural 5* item resistance goes to the half of the meter. This is very misleading and confusing. It's more effective to have two resistances uvs (low + medium) than going for a natural resistant set, and I'm okay with this, but if this is the way it works then please don't show it as something different. Don't put 3 bars of resistance when it should show only half a bar. Me and some friends have come to this conclusion by doing testing in the training hall, but if you don't believe it you can check yourself. I hope this get fixed sometime.

Unless some items scale down and some others don't, testing this in training hall or tier 3 should give the same results. I'm not talking about the amount of damage received, I'm talking about how a set with (supposedly) more resistance can take more damage of that status effect than another set with less resistance. The test itself was this: I was wearing a volcanic plate set and with the fire trap I got 4 seconds fire. My friend had a 5* Gunslinger set with a medium fire resistance uv on each piece and he couldn't get on fire. Also, I have medium shock resistance on both pieces of my volcanic plate set and I can't get shocked.
That's messed up. I know the bars lie... but come on. Wonder if it is a bug.

This is no bug, also the person Lufte was talking about that was there testing was me. Pupu has done similar tests here http://forums.spiralknights.com/en/node/10522 and I was curious to see if it was correct. Apparently each armor with natural resistances are equivalent to low UVs apiece.
A possible solution would be that UVs scale down less than natural resistances in ATH, but that would seem a little weird. In Pupu's testing he went to different depths to test out resistances and the outcome was similar, so I don't think this is wrong. Every time you see bars, take them with a grain of salt, as they can be as misleading as the descriptions.

Does this work the other way around? (Weaknesses)
So if I get say, a fire resist medium UV on an angelic helm and push it to Valkyrie, it cancels out the fire weakness business? O.o
A lot of items scale down in the training hall and lower tiers. Can you try it out in Tier 3 and see if the results are the same?