It WILL come out if you follow me.
Sight removal requires two things, and it will come out just fine, with a minimum of headache. I've removed many successfully. Failing to do either of the following will mean simply that it won't budge. Lube has
nothing to do with it. The metal is married so tightly that no useful lubrication will get in, anyway. Remember that sights are intentionally installed so they won't move under the repeated vibration of firing. The only way to move them is to use professional techniques.
First, be sure to clamp the barrel in a heavy machine vise directly under the front sight dovetail. It
MUST be clamped there, and it
MUST be in a solid machine vise of the 50 pound kind. The bench must have no vibration. Wee little vises and flimsy workbenches like they sell for doing hobbies just won't work. If you do any gun work, it'll be an asset for years. I reversed the steel pads years ago to the smooth side, which is what I did when I trained at Smith & Wesson in the 70s, and I can chuck a gun in without marring it. On to part two.
Secondly, the drift you use must be a solid piece of round brass or German silver bar stock, ground to to a flat wedge to precisely fit the height and width of standard dovetails. You don't want to dent the sight dovetail, which will actually broaden it and make it tighter. And, you certainly don't want to go near the edge and stake it, which will do likewise.
Place the drift exactly perpendicular to the barrel and parallel to the dovetail. You must position the drift low in the dovetail at the widest part to get the best advantage. Going high will twist it downward and defeat your effort. Using a 2 ounce ball peen hammer, drive confidently and with a straight stroke, from left to right. There's a correct sound associated with this procedure that will tell you when the sight is moving. A ringing sound means it's vibrating like a tuning fork. Be sure everything is tight, and drive harder. A thud means it's moving. If you're getting neither sound, see your local car mechanic and ask to use his vise.
Brownells sells sight pushers, but frankly, I think they work no better, and often they don't work at all.
If you do not have access to a machine vise, you may as well saw the sight off, for you'll do nothing except beat it to a pulp.