I think the best people are open to both, I also think if you're super into females and just enjoy watching dogs react or the way they feel, or you enjoy sharing and discussing with owners, you'll eventually get into both. Like a gay guy may end up trying pussy, I've also talked to people who started female and tried male ass, HuskyLust to namedrop one I spoke with.
Neither is "better", it depends on circumstance and personal preference. Honestly neither are for cowards, and both have certain times they're not totally clean, yes even pussy. Not sure where I'm going with this bye now.