Although this may not fully answer the question, I post this information as such because it looks into the cause (high wind) provided as a reason by the airline, and it is too much for a comment. If any user want to reuse this text as a basis for a more elaborate answer, please feel free to do so.
The aircraft initiated the go-around at approximately 20:15 UTC, from a height of 300 ft.
Other aircraft were able to land in the 30 minutes before and after the occurence. Most did on the first attempt, a few needed a second attempt.
The primary landing runway at the time was RWY 01, few aircraft circled to land at runway 33.
The weather according to the METARs around that time:
METAR KDCA 141952Z 31021G33KT 10SM BKN060 06/M09 A2990 RMK AO2 PK WND 28035/1921 SLP123 T00561089=
METAR KDCA 142052Z 30019G40KT 10SM BKN055 06/M09 A2991 RMK AO2 PK WND 28040/2043 SLP128 T00561089 53006=
The wind was from a direction of 300 to 310 degrees at around 20 knots, with gusts up to 40 knots.
Peak winds (measured during the past hour) were at 35 knots at 19:21 and 40 knots at 20:43 UTZ. These peak winds were from a more westerly direction of 280 degrees.
A gust from 280 degrees at 40 knots would be a 40kt crosswind component on RWY 01.
The same gust would be a 26 knots crosswind component on RWY 33.
The demonstrated crosswind component on the Embraer 170 is 28 kts sustained, with gusts to 38 kts on dry runways. On wet runways, the demonstrated crosswind component is 28 kts.
The conditions during the time of final approach were close to the maximum demonstrated crosswind, but probably not exceeding it.
Dulles airport (IAD) has a runway 30, with almost no crosswind component at the time.
I will not speculate to the reasons why no second approach was attempted, and why a diversion back to Canada was decided.