Python Delete point in a distance of x meters

I took this code from this source Select maximum number of points more than x meters apart

It seems to work for other users, but for me it’s an endless loop. I do not understand why, though the code makes sense. The code itself gives me the result I want to get.

Can you help me out of this endless loop:

#

import arcpy, sys

feature = arcpy.GetParameterAsText(0)
distance = 500

arcpy.gp.overwriteOutput = True

#running NEAR analysis - every point gets attribute of a distance to the nearest point 
#in same feature class
arcpy.AddMessage("running first near analysis")
arcpy.Near_analysis(feature, feature)

arcpy.AddMessage("inserting cursor")
cur = arcpy.UpdateCursor(feature)
row = cur.next()

arcpy.AddMessage("starting loop")

i=0
while row:
    i+=1
    #fids list will store list of deleted points so if any other point will have 
    #deleted one as the nearest and distance < 150 will not get deleted as this
    #distance is no longer true
    fids = []
    while row:
        if row.NEAR_DIST < distance:
            try:
                #it seems I didn't know if .. in .. at the time   such a fun to dig
                #this script up! index throws an exception if element is not in the 
                #list
                fids.index(row.NEAR_FID)
                arcpy.AddMessage("OBJECTID = " + str(row.OBJECTID) + " is listed!")
            except:
                arcpy.AddMessage("deleting OBJECTID = " + str(row.OBJECTID))
                fids.append(row.FID)
                cur.deleteRow(row)
                d = 1
        row = cur.next()
    del cur, row, fids
    try:
        #this idiotic test is to break the loop when no points will have 
        #NEAR_DIST < 150, shameful - I know!
        if d == 1:
            pass
    except:
        sys.exit()
    d = 0
    arcpy.AddMessage("loop iteration " + str(i))

    #and again we go..
    arcpy.Near_analysis(feature, feature)
    cur = arcpy.UpdateCursor(feature)
    row = cur.next()