During my first Passover after my (Reform) conversion I went out of my way to observe the laws 100% as much as possible, including details like having no candy bars because they contain corn syrup, for instance. That Passover experience had a radical anti-kashrut effect on me: far from bonding me to kashrut it made me decide that it was all hocus-pocus. It's inconsistent and dishonest to adopt what is effectively an Orthodox practice for one week of the year but ignore other such practices for the remaining 51 weeks of the year. While kashrut is a Jewish practice historically, it's not a Reform practice, historic or current. To me, adopting such dietary practices smacks of "play acting." It's a smoke and mirrors game which gives the illusion of Jewishness but doesn't actually mean or prove anything, certainly nothing Reform.
Far from it expressing insecurity, I think a Reform Jew who is against kashrut is being a tad more legitimate than those who claim to gain something from the relatively arbitrary choice not to eat certain things yet who don't follow the multitude of other "Jewish-making" practices, like not driving on Shabbat or turning on the lights. Reform takes its identity from other elements of religious life, not from relatively meaningless exercises which assume a "holiness" simply because they are done in the name of Judaism. However, this is a big Jewish tent we are all sitting under so a Reform Jew who follows kashrut isn't wrong in my eyes, just looking at it differently.
From CC, a Reform Male
Editor's Note: One clarification: the Reform movement, in the 1999 platform, called for a re-examination of traditional practices, like Kashrut. The movement encouraged Reform Jews to educate themselves in all the mitzvoth, to try doing them, and to make a conscious choice about which ones were meaningful to the individual. Consult your rabbi for a more detailed response to Reform observance.