A lot of posters are saying it's not the cycling, it's the time. Its say a whole day out of the weekend, or the activity holiday taking up annual leave. If the wife did that then there would be no family time.
Your argument is 'well its better that he is out cycling and engaged the rest of the time, than staying in bed / gaming / being at home but not present and engaged'.
And yes, that's true, but it isnt a case of one or the other. I'd personally prefer someone like my husband who is present and engaged at home, and does a hobby that takes him out for an hour at a time, 3x a week, and 2 of those hours over his lunch break. He isnt 'getting under my feet' or mooching about pissed off because he would rather be doing something else when he is here, he is doing his share of looking after our young kids and spending time together as a family at weekends as we both work so time as a family isnt really quality in the week. I imagine as they get older we will go off and do more things for ourselves (I am a cyclist but not fit enough to do it for long yet).
If we were on holiday with young kids and he disappeared for two or three days cycling, then I did the same, then our family holiday time together as a family would be halved, and as the kids are mostly in holiday clubs and school and nursery anyway we both want to see them on holiday
One thing I agree with you though is the comments about lycra/ looking ridiculous in lycra. Who cares, and people should exercise in what they feel comfortable about. I sometimes think that's why people dont state what their husbands hobby is because you get shit remarks about the hobby (eg stupid golf outfits, or gaming being an activity for teenagers only) rather than the actual problem