All of this are not the KM problems:
1) you must unload all program modules before uninstall it.
2) high memory consumption is the 'feature' of modern internet pages not browsers so you cannot reduce it under some level. The modern minimum is about 25-30 Mb for one opened page (tab) and can be achieved by KM with more chance than by any contender...
If you want get the maximum from K-Meleon without extra buzz, just use portable builds.
I recommend so named 'CommMeleon' (link in my signature) build - it includes many community recommended additions and tweaks...
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Using
K-Meleon-1.6.17db+ /
KM-16-S2014
1.6beta2.5 by JamesD
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Recommending K-Meleon Twin+
Try and
discuss it!!!