I don't have time to be vegan
Beans on toast, pasta, curries and stir-fries are quick. Most of the time cost is unfamiliarity, and it is temporary.
My days are already full with work, family and commuting, and the way I eat now runs on autopilot: I know what to buy, what to cook and what to grab when I'm exhausted. Going vegan means rebuilding all of that from scratch, checking labels, hunting down substitutes, learning new recipes and planning meals that actually fill me up, and I simply don't have spare hours in the week to spend on that. However worthwhile the goal, a diet that demands more time and attention than I can give is not one I can realistically keep up.
Learning any new way of cooking takes time at the start: reading labels, finding substitutes, working out what to keep in the cupboard. That cost is real and front-loaded.
Steady-state is a different matter. Lentil dal, pasta with tomato and beans, stir-fried vegetables and rice, chickpea curry, porridge, soup: these are not slower than their omnivorous equivalents, and several are faster, since there is no raw meat to handle separately. The genuine time constraints are the same ones that affect everybody's cooking, and they argue for a repertoire of quick meals rather than against the diet.
Inferring that one thing caused another from the fact that they occurred together or one after the other. Correlation and sequence are not causation.
How it applies here: Attributes the additional effort to plant-based food rather than to unfamiliarity, which attends any change in how someone cooks and resolves with practice.
Replacing someone's actual position with a weaker, distorted version, then refuting that instead. The original argument is left untouched.
How it applies here: Imagines vegan cooking as elaborate preparation from scratch, when most of it is ordinary weeknight food with different components.