Filtration is not harmful to your wine unless you go nuts with it and filter several times. But the harm there is really the potential oxidization.
Normally commercial wineries will age their wine in bulk and let gravity do the job of clearing. Before bottling, a technician will check the wine for clarity. If ok they wlll bottle, if not they may wait or filter. There are 3, 9, 12 and even 20 pad filters on the market!
In the home winemaking business, almost all kits (soon to be all) come with sachets of kiesosol and chitosan – truly magic stuff! Before they came along we had such things as bentonite (a clay) gelatine, isokleer… And before that: egg whites!!!
As long as the above were all we had, filtration was often a necessity. However, these days that is much less the case. But then there are some people who really care about the clarity of their wine. There are ways and means. Filtration is one of them. The other is a second shot of Superkleer – very rare is there a wine this does not clarify. But there is a drawback: an extra racking.
On a final note: 'The Stubborn wine'
Though most wines will clear through the process of fining, some refuse. There is a reason. Wine kits have been tested and balanced insofar as acid levels, tanin, nutrients and pectin. But Murphy's law still applies. There are time when a wine (mostly whites) refuse to clear.Filtration is then necessary. Why? Because of pectin (the culprit), a compound contained in grapes. Pectin is great to add if making jelly, but wine isn't something you want to be able to spread on toast. Enough pectic enzyme will usually fix it as the pectin is broken down and settles. It does not ferment as it is nonfermentable. That was fun!!!